JP4826200B2 - Biaxially oriented polyester film for molded parts - Google Patents

Description

  The present invention relates to a biaxially oriented polyester film, and more particularly to a biaxially oriented polyester film for a molded member that can be suitably used for a plating-like molded member that is molded after metal deposition on the film surface.

  2. Description of the Related Art In recent years, many members having a metallic appearance have been used by plating resin-molded materials such as building materials, automobile parts, mobile phones, and electrical products. However, as interest in environmental issues increases, the effect of the plating solution in the chemical bath when plating on the resin on the environment is being considered as a problem, and in particular, efforts to prevent the leakage of the plating solution are necessary. Furthermore, there is a movement to regulate the plating solution itself.

Under such circumstances, proposals have been made in recent years for performing metal deposition on a polyester film as a metal-like molded member in place of plating, and then molding the polyester film. Proposals have been made to apply metal vapor deposition to an unstretched polyester film and further use it as an automotive part by bonding it to another resin sheet (see, for example, Patent Document 1). However, in this proposal, unstretched film is used, so there is a problem in thermal dimensional stability, it is difficult to perform uniform metal deposition, and further, aging of parts after molding, chemical resistance Etc. have problems. Moreover, even if it is a biaxially oriented film, the proposal which uses a copolyester and uses as a shaping | molding member by using a film with comparatively low melting | fusing point is made | formed (for example, refer patent document 2, 3). However, in these proposed films, the crystallinity is kept low due to copolymerization, so that spherulite growth becomes noticeable during thermoforming, and the appearance as a molded member is caused by the cloudiness of the film before and after molding. There is a problem of being damaged. As a film that can solve these problems, an easily moldable film using polyethylene terephthalate having a high melting point has been proposed (see, for example, Patent Document 4). Since the stress is too high, it is difficult to mold the target member by thermoforming.
JP 2004-98485 A JP 2005-97528 A JP 2004-131546 A JP 2001-347565 A

  An object of the present invention is to eliminate the above-described problems. In other words, a film that has heat resistance and dimensional stability that can withstand uniform metal deposition, can be used for deep drawing, and has a degree of transparency that does not impair the appearance of the molded product after thermoforming. There is to do.

The present invention uses the following means in order to solve such problems. That is, the polyester film of the present invention can be achieved in a biaxially oriented polyester film for molded members having the following characteristics.
That is,
(I) A biaxially oriented polyester film for molded members having the following characteristics (1) to (5).

(1) having a laminated structure of at least three layers,
(2) The melting point of the polyester film is 246 ° C to 270 ° C,
(3) The crystal size of the (100) plane obtained by X-ray diffraction intensity is 6.0 nm to 8.0 nm,
(4) The elongation in the film longitudinal direction and the width direction at 190 ° C. is 150 to 300%,
(5) The plane orientation coefficient (fn) on both surfaces of the polyester film is 0.08 to 0.14,
(II) The biaxially oriented polyester film for molded members according to (I), wherein the surface haze (Hs) of the film satisfies the following formula a:
0.1 ≦ Hs ≦ 1.5 (a)
However, surface haze (Hs) = total haze (Ht) −internal haze (Hi).
(III) 50-90 mol% of the glycol residue component of the polyester resin constituting the film is ethylene glycol residue, 10-30 mol% is 1,4-butanediol residue, 0.1-10 mol% is other A biaxially oriented polyester film for molded members according to (I) or (II), which is a glycol residue component of
(IV) 95 to 99 mol% of the dicarboxylic acid residue component of the polyester resin constituting the film is a terephthalic acid residue, and 1 to 5 mol% is another dicarboxylic acid residue component ( Biaxially oriented polyester film for molded member according to any one of I) to (III),
(V) Vapor deposition characterized in that a metal compound having a melting point of 150 to 300 ° C. is vapor-deposited on at least one surface of the biaxially oriented polyester film for molded member according to any one of (I) to (IV). the film,
(VI) Biaxially oriented polyester for molded members, characterized in that an acrylic or urethane thermoplastic resin is coated or laminated on at least one surface of the polyester film according to any one of (I) to (V). the film,
It is.

  According to the present invention, since the film has a high elongation at 190 ° C., it can be easily formed into a desired shape and is excellent in thermal dimensional stability, so that uniform metal deposition can be easily performed. It can be suitably used for plated molded parts.

  The polyester resin constituting the polyester film of the present invention is a general term for polymer compounds in which the main bonds in the main chain are ester bonds, and is usually obtained by polycondensation reaction of a dicarboxylic acid component and a glycol component. Can do. 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.

  As the component constituting the polyester used in the present invention, the above-described dicarboxylic acid component and glycol component are preferably used. Furthermore, a polyester composed of a single dicarboxylic acid component such as polyethylene terephthalate, polyethylene-2, 6-naphthalenedicarboxylate and a glycol component is more preferably used. Furthermore, it is preferable from the viewpoint of productivity and economy that the recovered raw material collected from the polyester film of the present invention is mixed with the polyester film of the present invention within a range of 0.1 to 50% by weight.

  The biaxially oriented polyester film for molded member of the present invention needs to have a laminated structure of at least 3 layers from the viewpoints of heat resistance, dimensional stability, suitability for metal deposition, appearance, and the like. In a laminated structure of two layers or less, heat resistance, dimensional stability, and film forming process stability are inferior, and there is a problem in handling properties such as curling of the film during secondary processing of the film to be thermoformed.

  Moreover, the biaxially oriented polyester film for molded members of the present invention has a melting point of 246 to 270 ° C. When the melting point is 245 ° C. or lower, the heat resistance is inferior, and whitening of the film may be observed during secondary processing of the film to be thermoformed. On the other hand, if the melting point exceeds 270 ° C., the melting point becomes too high, and the adhesion with the metal thin film layer may be inferior when the metal is deposited. From the viewpoint of both heat resistance and deposition suitability, the melting point is preferably 246 to 265 ° C, more preferably 246 to 255 ° C. Here, the melting point of the polyester film is an endothermic peak temperature that is manifested by a melting phenomenon when measured with a differential scanning calorimeter (DSC) at a heating rate of 20 ° C./min. When blended polyester resins having different compositions are used, a plurality of endothermic peaks due to melting may appear. In this case, the endothermic peak temperature appearing at the highest temperature is set to the temperature of the polyester film of the present invention. The melting point. As a method of setting the temperature range to apply the melting point of the polyester film, 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.

  In addition, the polyester film of the present invention needs to have a (100) plane crystal size obtained by X-ray diffraction intensity of 6.0 nm to 8.0 nm, preferably 6.5 nm to 8.0 nm, more preferably Is 6.5 to 7.5 nm. When the crystal size of the (100) plane is 6.0 nm or less, it is not preferable because the degree of crystallinity is insufficient and the film undergoes thermal shrinkage during thermoforming, resulting in poor dimensional stability. On the other hand, when the thickness is 8.0 nm or more, the thermal shrinkage is small, but the film is fragile due to disorder of molecular orientation, and the film is broken at the time of molding, and the film is broken at the time of film formation. Here, the crystal size of the (100) plane is obtained by reflection X-ray diffraction using the Scherrer equation. The crystal size of the (100) plane of 6.0 nm to 8.0 nm is determined by the polymer constituting the film, additives, stretching conditions, heat treatment conditions, and the like, and can be achieved by arbitrarily setting these. For example, the heat treatment temperature may be increased or the heat treatment time may be increased, but it must be within a range that satisfies the characteristics required for the film.

  The polyester film of the present invention needs to have an elongation of 150 to 300% in the film longitudinal direction and the width direction at 190 ° C. Preferably it is 180-300%, More preferably, it is 180-280%. If the elongation of the polyester film is 150% or less, it is not preferable because tearing occurs at the time of molding or shape followability deteriorates. Moreover, if it is 300% or more, it may not be able to withstand the tension for transferring the film in the vapor deposition process or the preheating process in the molding process at the time of molding, and the film may be deformed or broken in some cases. The merchandise value may be lost.

  The biaxially oriented polyester film for molded members of the present invention needs to have a plane orientation coefficient of 0.08 to 0.14. Preferably it is 0.10-0.14, More preferably, it is 0.10-0.135. Thereby, the elongation of the film longitudinal direction and the width direction at 190 ° C. can be 150 to 300%.

  Further, taking the stretching conditions that can satisfy the orientation in which the absolute value of the refractive index difference between the film longitudinal direction and the width direction is 0.001 to 0.03 satisfies the elongation in the film longitudinal direction and the width direction at 190 ° C. from 150 to It is preferable from a viewpoint to set it as 300%. Specifically, it is a condition of 2.5 to 3.5 times at a temperature of 90 to 130 ° C. in the longitudinal direction and the width direction of the film, respectively, and the surface magnification (longitudinal draw ratio × width draw ratio) is In the case of 7 to 11 times, the elongation at 190 degrees of the present invention can be achieved.

  Moreover, in the heat setting process after extending | stretching, it is preferable that heat processing temperature shall be 200-240 degreeC at the point which relieve | moderates the crystal orientation by extending | stretching. Furthermore, in addition to the preferable film forming conditions, it is preferable that 5 to 50% by weight of the polyester resin to be used is a resin having a glass transition temperature of 0 to 60 ° C. By mixing and using a resin having a glass transition temperature to be applied, it is possible to stably realize low deformation stress at 150 to 200 ° C. In consideration of moldability and heat resistance, the addition amount of the polyester resin having a glass transition temperature (not the secondary transition point) of 0 to 60 ° C. is more preferably 10 to 40% by weight of the polyester resin to be used.

  The biaxially oriented polyester film for a molded member of the present invention preferably has a surface haze (Hs) satisfying the following formula a in terms of handleability and appearance as a molded member.

0.1 ≦ Hs ≦ 1.5 (a)
However, surface haze (Hs) = total haze (Ht) −internal haze (Hi).

  In the formula (a), if it is less than 0.1, the film surface is too smooth and does not slip, and surface scratches may occur in the process of transporting and winding the film. On the other hand, if it exceeds 1.5, even if metal vapor deposition is performed, it may appear cloudy when viewed through the film, and the appearance may be impaired. Here, (Ht-Hi) is preferably 0.2 to 1.4 from the viewpoint of handleability and moldability, and more preferably 0.3 to 1.3. As a method for making the film haze a preferable range, a method for reducing the content of particles described later in a range that does not impair the handleability of the film can be mentioned. When forming a polyester film, A / B / A type three-layer laminated film, with the A layer having a thickness of about the average particle diameter, specifically about 0.1 to 1.5 μm, and adding particles to the A layer and not adding particles to the B layer The method can be used. In addition, by using the method of forming a laminated film, the internal haze is reduced, and the surface haze can be reduced by laminating and applying a weather-resistant coating layer or adhesive such as a UV absorber. It can be used as an excellent molded member.

  In the polyester film of the present invention, from the viewpoint of moldability, 50 to 90 mol% of the glycol residue component constituting the polyester resin constituting the film is ethylene glycol residue and 10 to 30 mol% is 1,4-butanediol residue. It is preferable that 0.1 to 10 mol% of the group is another glycol residue component. The content of 1,4-butanediol residue is more preferably 15 to 25 mol%, and the other glycol residue components are more preferably 1 to 5 mol%. Here, each glycol residue component may be present by being copolymerized in the polyester, but if copolymerization is performed, the melting point may be lowered and the heat resistance may be deteriorated. Several polyester resins each having a glycol residue component alone may be blended and contained in the film, or blending and copolymerization may be used in combination. Other glycol residue components are not particularly limited, but include diethylene glycol residues, 1,4-cyclohexanedimethanol residues, neopentyl glycol residues, 1,3-propanediol residues, etc. Can be preferably mentioned. In addition, a plurality of glycol residue components may be included as other glycol residue components.

  Furthermore, from the viewpoint of moldability, the polyester film of the present invention has 95 to 99 mol% of the dicarboxylic acid residue component constituting the polyester resin constituting the film, and 1 to 5 mol% of the other is 1 to 5 mol%. The dicarboxylic acid residue component is preferred. The other dicarboxylic acid residue component is more preferably 1 to 3 mol%. The dicarboxylic acid residue component may be a dicarboxylic acid as a starting component or a dicarboxylic acid ester derivative as a starting component. Here, the terephthalic acid residue and the other dicarboxylic acid residue may be present by being copolymerized in the polyester, but if the copolymerization is performed, the melting point is lowered. A method of existing in the resin and blending the polyester resin in the film is preferable. Moreover, you may use copolymerization and a blend together. Other dicarboxylic acid residue components are not particularly limited, but 2,6-naphthalenedicarboxylic acid residue, isophthalic acid residue, 5-sodium sulfoisophthalic acid residue, adipic acid residue, sebacic acid residue Preferred examples include groups, dimer acid residues, 1,4-cyclohexanedicarboxylic acid residues and the like.

  The polyester film of the present invention preferably contains particles having an average particle diameter of 0.01 to 5 μm from the viewpoint of improving handleability and preventing scratches during processing. The 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 of particles. Moreover, the average particle diameter referred to here is the volume average particle diameter. As particles to be added, for example, internal particles, inorganic particles, and organic particles can be preferably used. In the polyester film of a preferred embodiment of the present invention, the particles are preferably 0.01 to 3% by weight, more preferably 0.03 to 3% by weight, still more preferably 0.05 to 2% by weight, in particular, based on the polyester film. Preferably 0.05 to 1 weight% can be contained.

  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.

  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. In addition, for the purpose of reducing the haze of the film as described above, when forming a polyester film, it is an A / B / A type three-layer laminated film, and the A layer has a thickness of about the average particle diameter, A method of adding particles only to the A layer and not adding particles to the B layer can be used.

  Next, the specific manufacturing method of the biaxially oriented polyester film for molded members of the present invention will be described. First, for the polyester resin used in the film of the present invention, commercially available polyethylene terephthalate resin and polybutylene terephthalate resin can be purchased and used as they are. For example, in the case of polyethylene terephthalate resin, polymerization is performed as follows. Can do.

  Magnesium acetate and antimony trioxide are added to a mixture of dimethyl terephthalate and ethylene glycol, the temperature is gradually raised, and finally the ester exchange reaction is performed while distilling methanol at 220 ° C. Next, an 85% aqueous solution of phosphoric acid is added to the transesterification reaction product, and then transferred to a polycondensation reaction kettle. The reaction system is gradually depressurized while being heated in the polymerization kettle, and a polycondensation reaction is performed at 290 ° C. under a reduced pressure of 1 hPa to obtain a polyethylene terephthalate resin having a desired intrinsic viscosity. In the case of adding particles, it is preferable to carry out polymerization by adding a slurry in which particles are dispersed in ethylene glycol to a polymerization reaction kettle so as to have a predetermined particle concentration.

  The production of polybutylene terephthalate resin can be performed, for example, as follows. A mixture of terephthalic acid and 1,4-butanediol was heated to 140 ° C. under a nitrogen atmosphere to obtain a homogeneous solution, and then tetra-n-butyl orthotitanate and monohydroxybutyltin oxide were added to esterify the mixture. Perform the reaction. Subsequently, tetra-n-butyl orthotitanate is added and a polycondensation reaction is carried out under reduced pressure to obtain a polybutylene terephthalate resin having a desired intrinsic viscosity.

  A preferred method for producing the film of the present invention using the polyester resin obtained as described above will be specifically described. First, when mixing the polyester resin to be used, it measures and mixes so that it may become a predetermined | prescribed ratio. Next, drying is performed, for example, at 150 ° C. for 5 hours in a nitrogen atmosphere, a vacuum atmosphere, or the like, and the moisture content in the polyester resin is preferably 50 ppm or less. Thereafter, it is supplied to an extruder and melt extruded. In addition, when performing melt extrusion using a vent type twin screw extruder, the resin drying step may be omitted. Next, foreign matter is removed and the amount of extrusion is leveled through a filter and a gear pump, and the sheet is discharged from the T die onto the cooling drum in a sheet form. In that case, for example, a method of applying static electricity using a wire-like electrode or a tape-like electrode, a casting method in which a water film is provided between a casting drum and an extruded polymer sheet, and a casting drum temperature from a glass transition point of a polyester resin to ( A sheet-like polymer is brought into close contact with the casting drum by a method of sticking the extruded polymer at a glass transition point of -20 ° C or a combination of these methods, and solidified by cooling to obtain an unstretched film. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness.

  Subsequently, the unstretched film is stretched in the longitudinal direction and then stretched in the width direction, or the stretched film is stretched in the width direction and then stretched in the longitudinal direction, or the longitudinal direction and the width direction of the film. The film is stretched by a simultaneous biaxial stretching method or the like that stretches almost simultaneously.

  As a draw ratio in such a drawing method, preferably 2.5 to 3.5 times, more preferably 2.8 to 3.5 times, and particularly preferably 3 to 3.4 times are employed in each direction. The The stretching speed is desirably 1,000 to 200,000% / min. The stretching temperature may be a glass transition point to (glass transition point + 50 ° C.), more preferably 90 to 130 ° C., particularly preferably a longitudinal stretching temperature of 100 to 120 ° C. and a stretching in the width direction. The temperature is preferably 90 to 110 ° C. Further, the stretching may be performed a plurality of times in each direction.

  Furthermore, the film is heat-treated after biaxial stretching. The heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. This heat treatment is carried out at a temperature of 120 ° C. or higher and below the melting point of the polyester, but is preferably a heat treatment temperature of 200 to 240 ° C. From the viewpoint of transparency and dimensional stability of the film, it is more preferably 210 to 235 ° C. The heat treatment time can be arbitrarily set within a range not deteriorating the characteristics, and is preferably 1 to 60 seconds, more preferably 1 to 30 seconds. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction. Furthermore, in order to improve the adhesive force with the ink print layer, the adhesive, and the vapor deposition layer, at least one surface can be subjected to corona treatment or a coating layer can be provided.

  As a method of providing the coating layer in-line within the film manufacturing process, at least uniaxial stretching is performed by uniformly applying a coating layer composition dispersed in water using a metalling ring bar, etc. A method of drying the coating while applying the coating is preferred, and in this case, the coating layer thickness is preferably 0.01 to 0.5 μm.

  Since the biaxially oriented polyester film for molded members of the present invention is also intended to be used as a molded member, it may be inferior in shape retention when the film thickness after molding is less than 10 μm. The film thickness is preferably 15 to 250 μm. If the film thickness exceeds 250 μm, no matter how much the deformation stress at the time of thermoforming is reduced, the actual load will increase, so there may be partial deformation, and it takes time to raise the temperature for the forming process. This may reduce productivity. Furthermore, as preferable film thickness, it is 18-100 micrometers, and it is especially preferable in it being 20-50 micrometers.

  The biaxially oriented polyester film for molded members of the present invention is preferably used by depositing a metal compound having a melting point of 150 to 300 ° C. on at least one surface of the film. By depositing and using a metal compound, the appearance becomes metallic, and it can be preferably used as an alternative to a molded part in which a currently plated resin is used. It is preferable to use a metal having a melting point within the range because the polyester film can be molded in a temperature range and the deposited metal layer can be molded, and the occurrence of defects in the deposited layer due to molding can be easily suppressed. A more preferable melting point of the metal compound is 150 to 250 ° C. Although it does not specifically limit as a metal compound whose melting | fusing point is 150-300 degreeC, Indium (157 degreeC) and tin (232 degreeC) are preferable, and indium can be used preferably especially.

  Further, as a method for producing a vapor deposition film, a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, an ion plating method, or the like can be used. In order to improve the adhesion between the polyester film and the vapor deposition layer, it is desirable that the surface of the film is pretreated by a method such as applying a corona discharge treatment or an anchor coating agent in advance. The thickness of the deposited film is preferably 1 to 500 nm, more preferably 3 to 300 nm. From the viewpoint of productivity, the thickness is preferably 3 to 200 nm.

  The biaxially oriented polyester film for molded member of the present invention is preferably provided with a weather resistant coating layer on at least one surface of the film from the viewpoint of maintaining quality when used in an outdoor environment. As a method of providing the coating layer, not only in-line coating in the film forming process described above but also off-line coating may be used. When a coating layer thickness of 1 μm or more is required, it is better to carry out coating off-line. preferable. Although it does not specifically limit as a coating agent used for a weather-resistant coating layer, It is a composition which can use water as a solvent used for application | coating, such as an acrylic type or urethane type thermoplastic resin. Is preferred.

  The biaxially oriented polyester film for molded members of the present invention has excellent molding processability, and can easily form molded parts that follow the mold in thermoforming such as vacuum and pressure forming, and before molding. By performing metal vapor deposition in advance, it can be suitably used as a part such as an automobile member or household appliance as a molded part having a plated appearance.

(1) Melting point About 10 mg of a sample was measured using a DSC7 manufactured by PERKIN-ELMER under conditions of a temperature of 30 to 300 ° C. and a heating rate of 20 ° C./min, and the endothermic peak temperature of the heat of fusion was taken as the melting point. When a plurality of endothermic peaks existed, the peak temperature of the endothermic peak on the highest temperature side was taken as the melting point.

(2) Crystal size The crystal size of the (100) plane was determined using a Scherrer equation with a reflection X-ray diffractometer (PW1728, manufactured by Philips). Here, the measured X-ray wavelength was 0.15418 nm (CuKα), and diffraction on the (100) plane was observed at a Bragg angle of about 25.8 °.

(3) Plane orientation coefficient (fn)
The refractive index of both surfaces of the polyester film was measured with an Abbe refractometer using sodium D line (wavelength 589 nm) as a light source and diiodomethane as an intermediate solution. The plane orientation coefficient was obtained from the refractive index (nMD, nTD, nZD) in the longitudinal direction, the width direction, and the thickness direction by calculating fn = {(nMD + nTD) / 2} -nZD.

(4) Elongation at 190 ° C. The film was cut into a short shape having a length of 150 mm × width of 10 mm in the longitudinal direction and the width direction to prepare a sample. Using a tensile tester (Orientec Tensilon UCT-100), an initial tensile chuck distance was set to 50 mm, and a tensile speed was set to 300 mm / min. In the measurement, a film sample was set in a constant temperature layer set in advance to a temperature of 190 ° C., and a tensile test was performed after 90 seconds of preheating. The elongation at break in each direction was determined from the obtained load-strain curve. In addition, the measurement was performed 5 for each sample and each direction, and the evaluation was performed with an average value of 3 points excluding the calculated maximum value and the minimum value.

(5) Film haze Based on JIS K 7105 (1985), it measured using the haze meter (HZ-2 by Suga Test Instruments Co., Ltd.). Moreover, the internal haze except a film surface haze was measured by putting the film into the quartz cell for liquid measurement, filling liquid paraffin, and performing the measurement. The surface haze was calculated by subtracting the internal haze from the total haze. The measurement was performed at three arbitrary locations, and the average value was adopted.

(6) Dimensional stability The film was cut into a rectangular shape with a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction to obtain a sample. Marks were drawn on the sample at intervals of 100 mm, and a heat treatment was performed by placing in a hot air oven heated to 150 ° C. with a 3 g weight suspended for 30 minutes. The distance between the marked lines after the heat treatment was measured, and the thermal shrinkage rate was calculated from the change in the distance between the marked lines before and after heating, and used as an index of dimensional stability. The measurement was carried out for each film with 5 samples in each direction, and the average value was evaluated.

(7) Polyester composition resin or film is dissolved in hexafluoroisopropanol (HFIP) or a mixed solvent of HFIP and chloroform, and the content of each monomer residue and by-product diethylene glycol using ¹ H-NMR and ¹³ C-NMR Was quantified.

(8) Intrinsic viscosity The intrinsic viscosity of the polyester resin and the film was measured at 25 ° C. using an Ostwald viscometer after dissolving the polyester in orthochlorophenol.

(9) Thermoformability Indium was sputtered to a thickness of 100 nm on one side of the film to form a vapor deposition film. The deposited film was heated to 300 ° C. using a far infrared heater heated to 300 ° C., and the film was formed by vacuum forming using a cylindrical mold (bottom diameter 50 mm). . The state of being molded along the mold was evaluated according to the following criteria using the molding degree (drawing ratio: molding height / bottom diameter).
Class A: Molding was possible with a drawing ratio of 0.7 or more.
Class B: Molding was possible with a drawing ratio of 0.7 to 0.3.
Class C: Breaking occurred and molding could not be performed with a drawing ratio of 0.3.

(10) Uniform moldability In the same manner as above, the indium vapor-deposited film is heated using a far-infrared heater at 350 ° C. so that the surface temperature becomes 180 ° C. A film was formed by vacuum forming using a mold having a bottom diameter of 50 mm, an interval of 30 mm, and 5 molds vertically and horizontally and 25 molds integrated. The state of being molded along the mold was visually observed and evaluated according to the following criteria.
Class A: All 25 pieces could be formed uniformly.
Class B: 24 to 20 pieces could be formed along the mold.
Class C: 19 or less could be formed along the mold.

(Manufacture of polyester)
The polyester resin used for film formation was prepared as follows.

(Polyester A :)
To a mixture of 100 parts by weight of dimethyl terephthalate and 67 parts by weight of ethylene glycol, 0.08 part by weight of magnesium acetate and 0.022 part by weight of antimony trioxide are added to dimethyl terephthalate, and the temperature is gradually raised. The transesterification was carried out while distilling methanol at ℃. Next, 0.019 part by weight of 85% aqueous phosphoric acid solution was added, and the temperature was gradually raised and reduced. Finally, the temperature was raised to 290 ° C. and 0.5 mmHg, and the pressure was reduced until the limiting viscosity reached 0.65. A condensation reaction was performed to obtain a polyethylene terephthalate resin having a by-product amount of 2% diethylene glycol.

(Polyester B :)
A mixture of 100 parts by weight of terephthalic acid and 110 parts by weight of 1,4-butanediol was heated to 140 ° C. under a nitrogen atmosphere to obtain a homogeneous solution, and then 0.054 parts by weight of tetra-n-butyl orthotitanate. Then, 0.054 part by weight of monohydroxybutyltin oxide was added, and esterification reaction was performed by a conventional method. Next, 0.066 part by weight of tetra-n-butyl orthotitanate was added, and a polycondensation reaction was performed under reduced pressure to produce a polybutylene terephthalate resin having an intrinsic viscosity of 0.84. 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 having an intrinsic viscosity of 1.20. This was designated as polyester B.

(Polyester C :)
In the polymerization of polyester A, instead of 100 parts by weight of dimethyl terephthalate, 90 parts by weight of dimethyl terephthalate and 10 parts by weight of dimethyl isophthalate are used for polymerization in the same manner as for polyester A. A polyethylene terephthalate resin (melting point: 228 ° C., diethylene glycol amount: 1.8 mol%) was prepared. This was designated as polyester C.

(Polyester D :)
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 part by weight of manganese acetate is added, and the temperature is gradually raised. The transesterification was performed while distilling methanol. Next, 0.045 parts by weight of 85% aqueous phosphoric acid solution and 0.01 parts by weight of germanium dioxide are added, and the temperature is gradually raised and reduced. Finally, the temperature is raised to 275 ° C. and 1 hPa, and the intrinsic viscosity is 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-state 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, whereby polyester D was obtained.

(Polyester E :)
Polymerization of polyester B was carried out in the same manner as for polyester B using 90 parts by weight of terephthalic acid and 10 parts by weight of isophthalic acid instead of 100 parts by weight of terephthalic acid, and 10 mol% isophthalic acid copolymerized polybutylene terephthalate. A resin (melting point: 210 ° C.) was prepared. This was designated as polyester E.

(Particle Master :)
Add 0.04 parts by weight of manganese acetate to a mixture of 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol, gradually increase the temperature, and finally perform transesterification while distilling methanol at 220 ° C. It was. Subsequently, 0.025 weight part of 85% phosphoric acid aqueous solution and 0.02 weight part of antimony trioxide were added. Further, an ethylene glycol slurry of aggregated particles having an average particle size of 2.2 μm is added so that the particle concentration becomes 2% by weight, the temperature is gradually raised and reduced, and finally the temperature is raised and reduced to 290 ° C. and 1 hPa. Then, the polycondensation reaction was performed until the intrinsic viscosity became 0.63 dl / g, and then discharged into a strand, cooled, and cut to obtain a particle master chip.

The abbreviations in the table are as follows.
EG: ethylene glycol residue component BD: 1,4-butanediol residue component TPA: terephthalic acid residue component DEG: diethylene glycol residue component CHDM: 1,4-cyclohexanedimethanol residue component IPA: isophthalic acid residue Base component (Example)
Examples of the present invention and comparative examples are shown below.

Example 1
As a polyester resin constituting the layer A, polyester A, polyester B, polyester D, and a particle master weight ratio of 59: 20: 20: 1 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A and particle master were mixed and used in a weight ratio of 97.5: 2.5. Each mixed polyester resin is individually dried in a vacuum dryer at 160 ° C. for 4 hours, supplied to separate single screw extruders, melted at 275 ° C., passed through filters and gear pumps in separate paths, foreign matter removed, After leveling the extrusion amount, the layers were laminated so as to be layer B / layer A / layer B (lamination thickness ratio 2: 21: 2) in the feed block installed on the top of the T die, and then the T die The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 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 3.2 times in the longitudinal direction at a film temperature of 96 ° C, and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 75 ° C. and a stretching temperature of 95 ° C. with a tenter-type transverse stretching machine, and the temperature was maintained at 230 ° C. for 2 seconds while relaxing 4% in the width direction in the tenter. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 25 μm.

(Example 2)
As a polyester resin constituting the layer A, polyester A, polyester B, polyester D and a particle master weight ratio of 65: 10: 23: 2 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A, polyester D, and particle master were mixed at a weight ratio of 88: 10: 2. Each mixed polyester resin is individually dried in a vacuum dryer at 150 ° C. for 5 hours, supplied to a separate single-screw extruder, melted at 275 ° C., passed through a filter and a gear pump in separate paths, to remove foreign matters, After leveling the extrusion amount, the layers were laminated so as to be layer B / layer A / layer B (lamination thickness ratio 1: 23: 1) in the feed block installed on the top of the T die, and then the T die The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 20 ° 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, finally stretched 3.2 times in the longitudinal direction at a film temperature of 97 ° C., and then a preheating temperature of 70 ° C. with a tenter-type transverse stretching machine, The film was stretched 3.1 times in the width direction at a stretching temperature of 100 ° C., and subjected to heat treatment for 2 seconds at 230 ° C. while relaxing 5% in the width direction in the tenter to obtain a biaxially oriented film having a film thickness of 25 μm. It was.

(Example 3)
As a polyester resin constituting the layer A, polyester A, polyester C and a particle master weight ratio of 63: 36: 1 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A and particle master were mixed and used in a weight ratio of 98.5: 1.5. Each mixed polyester resin is individually dried in a vacuum dryer at 150 ° C. for 5 hours, supplied to a separate single-screw extruder, melted at 275 ° C., passed through a filter and a gear pump in separate paths, to remove foreign matters, After leveling the extrusion amount, the layers were laminated so as to be layer B / layer A / layer B (lamination thickness ratio 1.5: 20: 1.5) in the feed block installed on the top of the T die. Thereafter, the sheet was discharged from a T die onto a cooling drum whose temperature was controlled at 20 ° 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, finally stretched 3.3 times in the longitudinal direction at a film temperature of 93 ° C., and then a preheating temperature of 70 ° C. with a tenter-type transverse stretching machine, The film was stretched 3.2 times in the width direction at a stretching temperature of 95 ° C., and then subjected to heat treatment for 2 seconds at a temperature of 220 ° C. while relaxing 5% in the width direction in a tenter, to form a biaxially oriented film having a film thickness of 23 μm. Obtained.

Example 4
As the polyester resin constituting the layer A, polyester A, polyester E, and a particle master weight ratio of 78: 20: 2 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A and particle master were mixed and used at a weight ratio of 99: 1. Each mixed polyester resin is individually dried in a vacuum dryer at 150 ° C. for 5 hours, supplied to separate single-screw extruders, melted at 270 ° C., passed through filters and gear pumps in separate paths, and removed foreign matter. After leveling the extrusion amount, the layers were laminated so as to be layer B / layer A / layer B (lamination thickness ratio 1: 18: 1) in the feed block installed on the top of the T die, and then the T die The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 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. Then, before stretching in the longitudinal direction, the film temperature is raised with a heating roll, finally stretched 3.2 times in the longitudinal direction at a film temperature of 95 ° C., and then a preheating temperature of 70 ° C. with a tenter type lateral stretching machine, The film was stretched 3.1 times in the width direction at a stretching temperature of 90 ° C., and then subjected to a heat treatment for 2 seconds at a temperature of 230 ° C. while relaxing 5% in the width direction in a tenter to obtain a biaxially oriented film having a film thickness of 25 μm. It was.

(Comparative Example 1)
As the polyester resin constituting the layer A, polyester A, polyester B, and a particle master weight ratio of 94: 5: 1 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A and particle master were mixed and used at a weight ratio of 95: 5. Each mixed polyester resin is individually dried in a vacuum dryer at 160 ° C. for 4 hours, supplied to separate single screw extruders, melted at 270 ° C., passed through filters and gear pumps in separate paths, and removed foreign matter. After leveling the extrusion amount, the layers were laminated so as to be layer B / layer A / layer B (lamination thickness ratio 2: 21: 2) in the feed block installed on the top of the T die, and then the T die The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 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, finally stretched 3.2 times in the longitudinal direction at a film temperature of 90 ° C., and then a preheating temperature of 90 ° C. with a tenter type transverse stretching machine, The film was stretched 3.1 times in the width direction at a stretching temperature of 110 ° C., and then heat-treated at 210 ° C. for 2 seconds while relaxing 5% in the width direction in a tenter to obtain a biaxially oriented film having a film thickness of 25 μm. It was.

(Comparative Example 2)
As the polyester resin constituting the layer A, polyester A, polyester E, and a particle master mass ratio of 68: 30: 2 were mixed and used. On the other hand, as the polyester resin constituting the layer B, polyester A and particle master were mixed and used in a mass ratio of 98: 2. Each mixed polyester resin is individually dried in a vacuum dryer at 160 ° C. for 4 hours, supplied to separate single screw extruders, melted at 275 ° C., passed through filters and gear pumps in separate paths, foreign matter removed, After leveling the amount of extrusion, after laminating to form a two-layer laminated film of layer A / layer B (lamination thickness ratio 23: 2) in a feed block installed on the top of the T die, the T die The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 20 ° 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 3.2 times in the longitudinal direction at a film temperature of 196 ° C. and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.2 times in the width direction at a preheating temperature of 75 ° C. and a stretching temperature of 95 ° C. with a tenter type horizontal stretching machine, and the temperature was maintained at 235 ° C. for 2 seconds while relaxing 4% in the width direction in the tenter. Heat treatment was performed to obtain a biaxially oriented film having a film thickness of 25 μm.

(Comparative Example 3)
Polyester C was used as the polyester resin. Polyester C is dried in a vacuum dryer at 180 ° C. for 3 hours, after sufficiently removing moisture, supplied to a single screw extruder, melted at 280 ° C., and sheeted on a cooling drum controlled to 25 ° C. from a T-die. It discharged in the shape. 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, finally stretched 3.2 times in the longitudinal direction at a film temperature of 90 ° C., and then a preheating temperature of 90 ° C. with a tenter type transverse stretching machine, The film was stretched 3.2 times in the width direction at a stretching temperature of 110 ° C., and then heat treated for 2 seconds at 240 ° C. while relaxing 3% in the width direction in a tenter to obtain a biaxially oriented film having a film thickness of 25 μm. It was.

The abbreviations in the table are as follows.
MD: film longitudinal direction TD: film width direction EG: ethylene glycol residue component BD: 1,4-butanediol residue component TPA: terephthalic acid residue component According to the examples satisfying the requirements of the present invention, Excellent formability, uniformity, handling and appearance. On the other hand, in the comparative example, surface scratches occurred in the film transporting process and the winding process, the moldability was inferior, and the film was markedly whitened by molding, resulting in inferior appearance. It was.

The biaxially oriented polyester film for molded members of the present invention has excellent molding processability, and can easily form molded parts that follow the mold in thermoforming such as vacuum and pressure forming, and before molding. By performing metal vapor deposition in advance, it can be suitably used as a part such as an automobile member or household appliance as a molded part having a plated appearance.

Claims (5)

The biaxially oriented polyester film for molded members having the following characteristics (1) to ( 5 ).
(1) having a laminated structure of at least three layers,
(2) The melting point of the polyester film is 246 ° C to 270 ° C,
(3) The crystal size of the (100) plane obtained by X-ray diffraction intensity is 6.0 nm to 8.0 nm,
(4) The elongation in the film longitudinal direction and the width direction at 190 ° C. is 180 to 300%,
(5) The plane orientation coefficient (fn) on both surfaces of the polyester film is 0.10 to 0.135,
(6) 81.2-88.7 mol% of the glycol residue component of the polyester resin constituting the film is an ethylene glycol residue,
9.2 to 18.0 mol% is 1,4-butanediol residue,
0.8-2.1 mol% is other glycol residue components. The surface haze (Hs) of the film satisfies the following formula a, The biaxially oriented polyester film for molded members according to claim 1.
0.1 ≦ Hs ≦ 1.5 (a)
However, surface haze (Hs) = total haze (Ht) −internal haze (Hi). 95 to 99 mole% of the dicarboxylic acid residue component of the polyester resin constituting the film is a terephthalic acid residue, claim 1, characterized in that 1 to 5 mol% are other dicarboxylic acid residue component or 2. A biaxially oriented polyester film for molded member according to 2. The vapor deposition film characterized by vapor-depositing the metal compound whose melting | fusing point is 150-300 degreeC on the at least single side | surface of the biaxially-oriented polyester film for molded members in any one of Claims 1-3 . At least one surface of the acrylic or urethane-based thermoplastic biaxially oriented polyester film for molded part of the resin is characterized by comprising coating or lamination of a polyester film according to any one of claims 1-4.