JP2010065065A - Polyester film for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester film which holds a stress low, when molded, and contains organic particles having a specific refractive index, and is excellent in transparency and a process-passing property. <P>SOLUTION: There is provided the polyester film for molding, containing organic particles having a refractive index of 1.5 to 1.65 in an amount of 0.001 to 1 mass% per 100 mass% of the total amount of the polyester film, and satisfying the following expressions (1) and (2): 1≤F100<SB>MD</SB>≤50 (1), 1≤F100<SB>TD</SB>≤50 (2), wherein, F100<SB>MD</SB>: a stress (unit: MPa) on the extension of 100% in the longitudinal direction at 150°C; F100<SB>TD</SB>: a stress (unit: MPa) on the extension of 100% in the widthwise direction at 150°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyester film for molding, and is particularly excellent in moldability, transparency and processability, so that various moldings such as insert molding and in-mold molding are possible, and the appearance after molding is also excellent. Therefore, the present invention relates to a molding polyester film that is suitably used for molding members such as building materials, automobile parts, mobile phones, and electrical products.

  In recent years, due to increasing environmental awareness, there has been an increasing demand for solvent-free coating and plating substitutes for building materials, automotive parts, mobile phones, electrical appliances, etc., and the introduction of decorative methods for molded parts using decorative sheets for molding has been introduced. Progressing.

Under such circumstances, several proposals have been made as molding polyester films. For example, a polyester film excellent in moldability having a specific melting point and elongation at break has been proposed (see, for example, Patent Document 1). Furthermore, a film in which polyethylene terephthalate and polybutylene terephthalate are mixed at 1: 1 to give formability is disclosed (for example, see Patent Document 2). However, these proposed films have a high deformation stress at the time of forming, so that it is difficult to form a complicated shape.
Further, a polyester film for molded members having a specific melting point and employing specific film forming conditions is also disclosed (for example, see Patent Document 3). Further, in order to achieve both formability, designability, and smoothness, a polyester film having a three-layer laminated film of an A layer, a B layer, and a C layer and having a moldability in the B layer of the intermediate layer has been proposed (for example, , See Patent Document 4). However, these polyester films do not have sufficient elongation at break and cannot withstand deep drawing.

In addition, a film that is a three-layer laminated film of an A layer, a B layer, and a C layer and contains particles only in the surface layer and has excellent moldability and transparency has been proposed (for example, Patent Document 5). However, since the refractive index of the particles used is different from that of the base film, the transparency is low and the slipping property is not sufficient.
JP 2001-72841 A JP 2002-321277 A JP 2003-221606 A JP 2006-51747 A JP 2007-111877 A

  An object of the present invention is to eliminate the above-described problems. That is, an object of the present invention is to provide a molding polyester film having excellent transparency and process passability by keeping stress during molding low and containing organic particles having a specific refractive index.

The present invention has the following configuration. That is,
(1) 100% by mass of the entire polyester film, 0.001 to 1% by mass of organic particles (A) having a refractive index of 1.5 to 1.65 are contained, and the following formulas (1) and (2) are satisfied. Polyester film for molding.
1 ≦ F100 _MD ≦ 50 (1)
1 ≦ F100 _TD ≦ 50 (2)
However, F100 _MD : Stress at 100% elongation in the longitudinal direction at 150 ° C. (unit: MPa)
F100 _TD : Stress at 100% elongation in the width direction at 150 ° C. (unit: MPa)
(2) As organic particles (A), organic particles (a1) having a particle size of less than 0.01 to 0.5 μm and organic particles (a2) having a particle size of less than 0.5 to 3 μm are contained. The forming polyester film according to (1).
(3) The forming polyester film according to (1) or (2), which is a laminated film comprising at least two layers, wherein the layer thickness of at least one layer is less than 0.1 to 3 μm.
(4) The forming polyester film according to any one of (1) to (3), wherein the average line center roughness after stretching 1.2 times each in the film longitudinal direction and the width direction at 200 ° C. is less than 1 to 20 nm.

  The polyester film for molding of the present invention is easy to be molded by thermoforming, and is excellent in transparency and processability, so it can be uniformly formed into a complex shape and has an excellent appearance after molding. Therefore, it can be suitably used for molding applications such as insert molding and in-mold molding, for example, molding materials such as building materials, automobile parts, mobile phones, and electrical products.

  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.

  As a glycol component used for the polyester film of this invention, it is preferable that it is comprised from 60-100 mol% of ethylene glycol components at the point of a moldability, an external appearance, heat resistance, and economical efficiency. As the glycol component contained in the molding polyester film of the present invention, in addition to ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1, Aliphatic dihydroxy compounds such as 5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, etc. Examples thereof include aromatic dihydroxy compounds such as alicyclic dihydroxy compounds, bisphenol A, and bisphenol S.

  Further, preferred dicarboxylic acid components used in the molding polyester film of the present invention include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid. , Aromatic dicarboxylic acids such as 5-sodiumsulfone dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid, etc. Examples thereof include oxycarboxylic acids such as alicyclic dicarboxylic acid and paraoxybenzoic acid. The dicarboxylic acid ester derivatives include esterified products of the above dicarboxylic acid compounds, such as dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, and dimethyl adipate. , Diethyl maleate, dimethyl dimer, and the like.

  The polyester film for molding of the present invention is particularly excellent in moldability, heat resistance, and transparency. In particular, 60 to 99 mol% of the glycol component constituting the polyester film is ethylene glycol and 1 to 30 mol% is 1,4-cyclohexane. Dimethanol is preferred. Inclusion of 1 to 30 mol% of 1,4-cyclohexanedimethanol can maintain a high melting point, maintain heat resistance, and suppress orientation crystallization during molding, thereby improving moldability. Can do. Furthermore, since it becomes possible to adjust crystallinity moderately, it becomes a film excellent also in transparency. Moreover, it is preferable to contain 1-30 mol% of 1, 4- butanediol and / or 1, 3- propanediol from the point which improves a moldability further. By including 1 to 30 mol% of 1,4-butanediol and / or 1,3-propanediol, molecular mobility during heating can be improved and stress during molding can be reduced. Can be improved. In order to further improve moldability and maintain heat resistance, 60 to 90 mol% of the glycol component constituting the polyester film is ethylene glycol, 2 to 25 mol% is 1,4-cyclohexanedimethanol, 10 to 35 The mol% is preferably 1,4-butanediol and / or 1,3-propanediol. More preferably, ethylene glycol is 60 to 80 mol%, 1,4-cyclohexanedimethanol is 3 to 20 mol%, and 1,4-butanediol and / or 1,3-propanediol is 15 to 30 mol%. .

  The polyester film for molding of the present invention has 0.001 organic particles (A) having a refractive index of 1.5 to 1.65 in order to achieve both process passability during molding and the appearance of the molded member after molding. It is necessary to contain ~ 1 mass%.

  Since the polyester film for molding used in the present invention is preferably used for a molded member after being subjected to molding such as insert molding or in-mold molding, in order to improve the appearance in addition to the step of winding the film during film formation. It passes through various processing processes such as coating, printing and metal deposition. Furthermore, a film transport process may be performed during molding. For this reason, in order to suppress the surface damage | wound in these process steps and to improve a conveyance property, it is necessary to give a slipperiness to a polyester film. Moreover, in order to make the external appearance of the molded member excellent, the transparency of the film is very important. The polyester film for molding of the present invention contains 0.001 to 1% by mass of organic particles whose refractive index is controlled to 1.5 to 1.65 which is close to that of the polyester film, so that these process passability and transparency can be achieved. It has been found that both are compatible.

  If the refractive index of the organic particles contained is less than 1.5, the difference in refractive index from the molding polyester film of the present invention is large, so fine white spots due to the particles are seen on the film, and the transparency is high. It will decline. Similarly, good transparency cannot be obtained when the refractive index is greater than 1.65. More preferably, the refractive index of the organic particles contained is 1.52 to 1.64, and most preferably 1.53 to 1.63.

  On the other hand, when the content of the organic particles is less than 0.001% by mass, sufficient slipperiness cannot be obtained and process passability becomes insufficient. On the other hand, when the content of the organic particles is more than 1% by mass, the transparency is deteriorated even if the refractive index is controlled in the range of 1.5 to 1.65. The content of the organic particles is more preferably 0.005 to 0.5% by mass, and most preferably 0.01 to 0.1% by mass.

  Moreover, the polyester film for molding of the present invention further improves the transparency and makes the process passability compatible, and as particles (A), organic particles (a1) having a particle size of less than 0.01 to 0.5 μm. It is preferable that at least two kinds of organic particles (a2) having a particle size of less than 0.5 to 3 μm are contained.

  Compared to the case of containing only one kind of particles by combining small particles (a1) with a particle size of less than 0.01 to 0.5 μm and large particles (a2) with a particle size of less than 0.5 to 3 μm. In addition, even if the content of the entire particle is kept low, the process passability does not decrease, so it is very effective for achieving both transparency and process passability. Each particle concentration is 100% by mass of the entire polyester film, 0.0005 to 0.995% by mass of particles (a1) having a particle size of less than 0.01 to 0.5 μm, and 0.5 to 0.005 to 0.995% by mass of particles (a2) of less than 3 μm is preferable. Furthermore, the process passability improves more when the particle (a1) concentration with a particle size of less than 0.01 to 0.5 μm is higher than the particle (a2) concentration with a particle size of less than 0.5 to 3 μm. Is preferred.

  The organic particles (A) having a refractive index of 1.5 to 1.65 used in the molding polyester film of the present invention have a spherical and uniform particle size distribution from the viewpoint of easy slipping and transparency. Is preferred. Furthermore, a monodispersed system is preferable in order to improve the slipperiness and transparency.

  The organic particles (A) used are not particularly limited. For example, as the organic particles, styrene, silicone, acrylic acid, methacrylic acid, polyesters, polyimides, melamines, epoxies, divinyl compounds and the like are constituent components. Can be used. Among these, crosslinked polystyrene is preferably used in terms of heat resistance and refractive index. Moreover, as a composition of a polystyrene particle here, since heat resistance improves, it is preferable to set it as styrene-divinylbenzene. Here, the concentration of divinylbenzene is preferably 10 to 70% by mass from the viewpoint of heat resistance, more preferably 15 to 65% by mass, and most preferably 20 to 60% by mass.

  Examples of a method for controlling the refractive index of the organic particles (A) include a method of copolymerizing an organic compound. For example, a cross-linked polystyrene-acrylic copolymer obtained by copolymerizing acrylic with cross-linked polystyrene is a preferred embodiment because the refractive index can be easily controlled and the heat resistance is hardly lowered.

  Moreover, you may add an inorganic particle to the grade which does not impair the effect of this invention to the polyester film for shaping | molding of this invention. The inorganic particles used here are not particularly limited. For example, wet and dry silica, colloidal silica, aluminum silicate, titanium dioxide, calcium carbonate, calcium phosphate, barium sulfate, aluminum oxide, etc., wet and dry silica, Alumina etc. are mentioned.

  Moreover, the method of containing the organic particles (A) used in the present invention is not particularly limited, and examples thereof include a method of adding at the time of polyester production and a method of kneading the polyester resin. From the viewpoint of particle dispersibility, a method of adding to the polyester production stage is more preferable, and in that case, it is preferable to add at a stage during the polymerization reaction from the start of polyester polymerization in order to improve dispersibility. The addition of particles in the precursor stage or polycondensation stage for producing the polyester resin composition is more preferably a method of adding as a slurry of ethylene glycol, and the concentration of the slurry at that time is preferably from the viewpoint of dispersibility. 5 to 20% by weight is preferred.

Since the molding polyester film of the present invention is molded into a molded member through molding processes such as insert molding and in-mold molding, it is necessary to satisfy the following formulas (1) and (2) from the viewpoint of moldability. .
1 ≦ F100 _MD ≦ 50 (1)
1 ≦ F100 _TD ≦ 50 (2)
However, F100 _MD : Stress at 100% elongation in the longitudinal direction at 150 ° C. (unit: MPa)
F100 _TD : Stress at 100% elongation in the width direction at 150 ° C. (unit: MPa)
The molding process of a molded member such as insert molding or in-mold molding includes a process of thermoforming such as vacuum molding, pressure molding, plug assist molding after a preheating process using an infrared heater or the like. The forming polyester film may be bonded to a base material to be formed. Examples of the base material include a thermoplastic resin sheet, a metal plate, paper, and wood. Especially, since a thermoplastic resin sheet is preferably used in terms of moldability, it is often molded at about 150 ° C., which is a temperature at which the base material is easy to mold. For this reason, even if it is a polyester film for a shaping | molding, the shaping | molding stress in 150 degreeC shall be a specific range, and uniform shaping | molding will be attained and shaping | molding also to a complicated shape will be attained.

If 1> F100 _MD or 1> F100 _TD , the preheating process in the molding process cannot withstand the tension for transferring the film, and the film may be deformed or broken in some cases. It may not be used as a polyester film. On the contrary, in the case of F100 _MD > 50 or F100 _MD > 50, deformation is insufficient at the time of thermoforming, and it is difficult to form into a complicated shape, so that sufficient characteristics as a polyester film for molding may not be satisfied. is there.

More preferably, the expressions (1) ′ and (2) ′ are preferably satisfied, and the expressions (1) ″ and (2) ″ are most preferable.
2 ≦ F100 _MD ≦ 35 (1) ′
2 ≦ F100 _TD ≦ 35 (2) ′
3 ≦ F100 _MD ≦ 20 (1) ″
3 ≦ F100 _TD ≦ 20 (2) ″
Here, the stress at 100% elongation (F100 value) of the film at 150 ° C. in the present invention will be described. A film sample cut into a rectangular shape with a test length of 50 mm is preheated for 90 seconds in a constant temperature layer set at 150 ° C., and then a stress value at 100% elongation when a tensile test is performed at a strain rate of 500 mm / min. The stress at 100% elongation (F100 value) was used.

In order for the forming polyester film in the present invention to satisfy the formulas (1) and (2), it is preferably stretched 2.5 to 3.5 times in the longitudinal direction and the width direction of the film at a temperature of 90 to 130 ° C., respectively. And it is preferable that surface magnification (longitudinal direction draw ratio x width direction draw ratio) is 7 to 11 times. Moreover, in the heat setting process after extending | stretching, since the orientation of the amorphous part of a film can be relieve | moderated by making heat processing temperature into high temperature, it is preferable. A preferable heat treatment temperature is 200 to 255 ° C, and more preferably 210 to 245 ° C. Moreover, it is a preferable aspect to extend | stretch on the above conditions and to make a plane orientation coefficient into 0.02-0.14. Here, the plane orientation coefficient (fn) is a numerical value defined by the refractive index of the film measured with an Abbe refractometer or the like. The refractive index in the longitudinal direction of the film is n _MD and the refractive index in the width direction is n. _TD, and the refractive index in the thickness direction and _{n ZD,} represented by the relational expression _{fn = (n MD + n TD} ) / 2-n ZD. In the case of a film having a plane orientation coefficient of less than 0.02, that is, almost non-oriented, the dimensional stability may be inferior. On the other hand, when the plane orientation coefficient exceeds 0.14, the moldability is deteriorated and the formulas (1) and (2) may not be satisfied. A more preferable range is 0.03 to 0.135, and 0.04 to 0.13 is most preferable.

  The molding polyester film of the present invention preferably has a film haze of 0.1 to 3% in terms of appearance and gloss as a molded member. If the haze exceeds 3%, the appearance of the film appears to be clouded, and the appearance and design may be inferior. On the other hand, if the haze is less than 0.1%, the film slips poorly, handling becomes difficult, scratches are generated on the film surface, and wrinkles are easily generated when the film is wound into a roll shape. In addition to adversely affecting the appearance as a molded member, the handleability of the film itself is deteriorated. From the appearance as a molded member, the more preferable range of haze is 0.2 to 2.5%, and 0.3 to 2% is particularly preferable.

  As a method of setting the haze of the molding polyester film of the present invention to 0.1 to 3%, the whole polyester film is 100% by mass, and the organic particles having a refractive index of 1.5 to 1.65 are 0.001 to 1. Although it is effective to contain by mass%, there is a method in which a laminated film comprising at least two layers is used and particles are contained only in at least one layer. By setting it as the above laminated structures, the particle density | concentration of the whole polyester film can be reduced, and a haze can be kept lower.

  Further, the molding polyester film of the present invention is a laminated film composed of at least two layers in order to further enhance the effect of particle slipperiness, and the layer thickness of at least one layer is less than 0.1 to 3 μm. It is preferable to do. The particle size of the organic particles used in the present invention is not particularly limited, but the particle size is preferably less than 0.01 to 3 μm from the viewpoint of easy slipping and transparency. For this reason, since the particles are more uniformly dispersed on the film surface by setting the layer thickness to less than 0.1 to 3 μm, this is a very preferable embodiment because the effect of easy slipping is enhanced. Moreover, since the particle | grain density | concentration of the whole film can be reduced by making layer thickness as thin as less than 0.1-3 micrometers, it is very advantageous also in transparency.

  Moreover, the polyester film for molding of the present invention can have a three-layer structure of A layer / B layer / C layer. A three-layer structure is preferable because curling due to heating during film processing can be suppressed.

In addition, in the case of a three-layer structure of A / B / C, by adding particles (A) only to the A layer or only to the C layer, both transparency and process passability can be achieved. It is preferable to add the particles (A) only to the layer and the C layer because the slipperiness of both sides of the film can be imparted.
From the viewpoint of economy and productivity, it is preferable that the polyester constituting the A layer and the polyester constituting the C layer have the same composition. Furthermore, in order to improve economy and productivity, it is preferable that the layer thicknesses of the A layer and the C layer are equal.

  When the molding polyester film of the present invention has a laminated structure, the interlayer adhesion between the A layer and the B layer is preferably 5 (N / 15 mm) or more in order to prevent peeling between the layers after molding. If the interlayer adhesion between the A layer and the B layer is less than 5 (N / 15 mm), the polyester film or a molded member using the polyester film is molded and then peeled off at the interface of the A layer / B layer. May occur. The interlayer adhesion is more preferably 8 (N / 15 mm) or more, and most preferably 12 (N / 15 mm) or more.

  The interlaminar adhesion force here refers to the value (peeling strength) at that time when peeling is forcibly generated at the interface of the A layer / B layer, and then the load applied during peeling is measured by a tensile test or the like. Point to. Specifically, an adhesive having a strength higher than the adhesion at the interface of the A layer / B layer is applied to the film sample, and the film for bonding is bonded thereon. The film for bonding used here is not particularly limited, and examples thereof include a polyester film, a polypropylene film, and a polyethylene film.

  The bonded sample is cut out to a width of 15 mm, and the peel strength when the 180 ° peel test is performed at a speed of 300 mm / min is defined as the interlayer adhesion (N / 15 mm) between the A layer and the B layer.

  In order to make the interlayer adhesion between the A layer and the B layer within the above range, it is effective to make the polyester A constituting the A layer and the polyester B constituting the B layer have similar compositions.

  In addition, it is effective to improve the adhesion by disturbing the interface between the A layer and the B layer by melting a part of the polyester A or the polyester B during the heat treatment during film production. For example, polyester A or polyester B contains a polyester resin having a melting point of about 220 ° C. to 230 ° C., such as polybutylene terephthalate and polytrimethylene terephthalate, and the heat treatment temperature is set to 220 ° C. or higher, so that the above polyester is melted. In addition, the interface is disturbed and the interlayer adhesion can be improved.

  The molding polyester film of the present invention preferably has a static friction coefficient of 0.2 to less than 1 and a dynamic friction coefficient of 0.2 to less than 0.8 from the viewpoints of handleability, winding property, and processability. A static friction coefficient of less than 0.2 is not preferable because the film may be displaced from the product roll. On the other hand, when the coefficient of static friction is 1 or more, the slipperiness of the film is lowered, so that the handling property and the winding property are lowered, and further, the film is not smoothly conveyed even in the processing step, and the yield is reduced and the processing unevenness is caused. The static friction coefficient that is generated is more preferably 0.3 to 0.8, and most preferably 0.4 to 0.7. Similarly, if the dynamic friction coefficient is less than 0.2, the slipperiness of the film is too high, and the film may be displaced during winding or processing. Further, when the dynamic friction coefficient is 0.8 or more, the workability is degraded. The dynamic friction coefficient is preferably 0.25 to 0.7, and most preferably 0.3 to 0.6.

  A method for setting the static friction coefficient and the dynamic friction coefficient within the above ranges is not particularly limited, but it is possible to select a particle having a uniform particle size distribution and a monodisperse system. In addition, a method of controlling the surface roughness by adjusting the particle concentration as appropriate is preferably used.

  The molding polyester film of the present invention has a static friction coefficient of 0.2 to less than 1, a dynamic friction coefficient of less than 0.2 to less than 0.8, and a center line average roughness of less than 1 to 20 nm in order to achieve both transparency. It is preferable that If the center line average roughness is to be less than 1 nm, the film has no irregularities and the process passability may be reduced. Further, when the center line average roughness before forming is 20 nm or more, the smoothness of the film is low and the glossiness of the film may be lowered, so that the appearance of the molded member may be lowered.

  Further, the polyester film for molding of the present invention has an average line center roughness of 1 to 20 nm after being stretched 1.2 times in the film longitudinal direction and the width direction at 200 ° C. in order to keep the appearance after molding beautiful. It is preferable that it is less than. If the center line average roughness after stretching the film 1.2 times in the longitudinal direction and the width direction at 200 ° C. is 1 nm, the center line average roughness before molding needs to be less than 1 nm. There may be no unevenness and the process passability may be reduced. In addition, when the center line average roughness after stretching the film at 200 ° C. by 1.2 times in the longitudinal direction and the width direction is set to 20 nm or more, the glossiness of the film surface after molding is reduced, The appearance may be inferior.

More preferably, the center line average roughness after stretching 1.2 times each in the film longitudinal direction and the width direction at 200 ° C. is less than 2 to 15 nm, and most preferably less than 3 to 10 nm.
In order to make the center line average roughness after stretching 1.2 times each in the film longitudinal direction and the width direction at 200 ° C. to be less than 1 to 20 nm, it is effective to contain 0.001 to 1% by mass of organic particles. Furthermore, the total particle concentration can be reduced by containing at least two kinds of organic particles having a particle size of 0.01 to less than 0.5 μm and a particle size of less than 0.5 to 3 μm. Therefore, it becomes easy to control the center line average roughness to 1 to 20 nm.

  Moreover, in order to make centerline average roughness after extending | stretching 1.2 times each in a longitudinal direction and the width direction at 200 degreeC to 1-20 nm, the centerline average roughness before extending | stretching shall be 1-20 nm. Is effective. Furthermore, it is also effective to improve the heat resistance of the molding polyester film of the present invention. In order to improve heat resistance, it is preferable that melting | fusing point is 220-260 degreeC. When the melting point exceeds 260 ° C., the heat resistance is too high, so that the deformation stress when the film is secondarily processed may be high, and it becomes difficult to form into a complicated shape. On the other hand, when the melting point of the polyester is less than 220 ° C., the heat resistance is lowered, and the center line average roughness after stretching 1.2 times in the longitudinal direction and the width direction at 200 ° C. is greater than 20 nm. And the appearance after molding deteriorates. From the viewpoints of moldability and heat resistance, the melting point is more preferably 230 to 255 ° C, and most preferably 235 to 250 ° C. The melting point here is an endothermic peak temperature which is manifested by a melting phenomenon when measured at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter. When polyester resins having different compositions are blended and used to form a film, a plurality of endothermic peaks accompanying melting may appear. In this case, the endothermic peak temperature appearing at the highest temperature is defined as the melting point.

  Furthermore, it is also effective to improve the affinity between the organic particles (A) to be added and the polyester resin. By preventing the generation of voids between the polyester and the particles after stretching 1.2 times each in the longitudinal direction and the width direction at 200 ° C. by improving the affinity between the organic particles (A) and the polyester resin. It is possible to prevent the center line average roughness from increasing. Improving the affinity between the organic particles (A) and the polyester resin is also very effective for controlling the haze to less than 0.1 to 3%.

  A method for improving the affinity between the organic particles (A) and the polyester resin is not particularly limited, but it is effective to perform a surface treatment on the organic particles (A). For example, the affinity with a polyester resin can be improved by introducing a functional group such as a carboxyl group, a hydroxyl group, an amide group, or a sulfonic acid group by surface treatment.

  Next, although the specific manufacturing method of the polyester film of this invention is described, it is not limited to this. First, a polyester resin containing organic particles (A) is prepared. For example, drying is performed at 180 ° C. for 4 hours in a nitrogen atmosphere, a vacuum atmosphere, or the like, respectively, and the moisture content in the polyester is preferably 50 ppm or less. When two or more kinds of polyesters are mixed, they are weighed and mixed at a predetermined ratio and dried. Thereafter, it is supplied to an individual extruder and melt extruded. When supplying polyester to an extruder, a nucleating agent may be blended and supplied. 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, respectively, and discharged from the T die onto a cooling drum in a sheet form. In the case of a laminated structure of two or more layers, for example, a feed block or a multi-manifold installed on the top of the T die is laminated to form an A / B type two-layer laminated film, and then the sheet is placed on the cooling drum from the T die. To be discharged. In the case of forming an A / B / C type three-layer laminate and a film, polyester A, polyester B, and polyester C are supplied to individual extruders and melt extruded. If polyester A and polyester C have the same composition, a three-layer laminated film of A layer / B layer / A layer can be formed by a feed block or multi-manifold with two extruders. When discharging into a sheet on a cooling drum, for example, a method of applying static electricity using a wire electrode or a tape electrode, a casting method of providing a water film between a casting drum and an extruded polymer sheet, and a casting drum temperature The sheet polymer is brought into close contact with the casting drum by the method of adhering the extruded polymer from the glass transition point of the polyester resin to (glass transition point−20 ° C.) or by combining these methods, and then solidified by cooling. An unstretched film is obtained. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness. Although the polyester film of the present invention exhibits excellent characteristics even when used as an unstretched film, it is preferably biaxially stretched in terms of heat resistance and dimensional stability. As a method for stretching an unstretched film, the film is stretched in the longitudinal direction and then stretched in the width direction, or the film is stretched in the width direction and then stretched in the longitudinal direction, or the longitudinal direction and width of the film. Examples thereof include a simultaneous biaxial stretching method in which the directions are stretched 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 preferably 1,000 to 200,000% / min. The stretching temperature is preferably 80 to 130 ° C, more preferably 85 to 120 ° C in the longitudinal direction and 90 to 110 ° C in the width direction. 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 255 ° C. From the viewpoint of transparency and dimensional stability of the film, it is more preferably 210 to 245 ° 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 in the film manufacturing process, at least uniaxially stretched film with a coating layer composition dispersed in water is uniformly applied using a metalling ring bar or gravure roll. Then, a method of drying the coating while stretching is preferable, and in this case, the coating layer thickness is preferably 0.01 to 0.5 μm.

In the present invention, the molding polyester film is very excellent in moldability, transparency, and processability, so various moldings such as insert molding and in-mold molding are possible, and the appearance after molding is also excellent. It is suitably used for molding materials such as building materials, automobile parts, mobile phones, and electrical products. Here, in-mold molding is a molding method in which a film itself is placed in a mold and molded into a desired shape with a resin pressure to be injected to obtain a molded decorative body. In insert molding, a film molded body to be installed in a mold is prepared by vacuum molding, vacuum / pressure forming, plug assist molding, etc., and a molded decorative body is obtained by filling the shape with resin. This is a molding method. Since a more complicated shape can be produced, the polyester film of the present invention is particularly preferably used for insert molding.
When used for insert molding, an easy-adhesion layer may be provided on the resin side surface of the film in order to enhance the adhesion to the resin to be injection molded. As the resin for injection molding, polycarbonate, ABS (acrylonitrile-butadiene-styrene), AS (acrylonitrile-styrene), polypropylene, polymethyl methacrylate, TPO (Thermo Plastic Olefin elastomer) or a mixed resin thereof is preferably used. It is preferable that the adhesiveness with the resin is high. Although it does not specifically limit as an easily bonding layer, Polyester type, urethane type, an acrylic type, a chlorinated polypropylene type etc. are mentioned.

  When the molding polyester film of the present invention is used for insert molding, the thickness is preferably 75 to 500 μm in terms of depth and shape retention of the molded body after molding, and if it is 100 to 300 μm. More preferably, it is most preferable if it is 150-250 micrometers.

  Further, the molding polyester film of the present invention can be used by being bonded to a molding substrate. By laminating with the molding substrate, a molding decorative sheet composed of the molding substrate / polyester film is obtained. Furthermore, when the weather resistance coating is given to the polyester film, it becomes the structure of the base material for shaping | molding / polyester film / weather resistance layer.

  Although it does not specifically limit as a base material for shaping | molding, A resin sheet, a metal plate, paper, wood, etc. are mentioned. Among these, a resin sheet is preferably used in terms of moldability, and a thermoplastic resin sheet is preferably used in terms of high moldability.

  Here, the thermoplastic resin sheet is not particularly limited as long as it is a polymer sheet that can be thermoformed. However, an acrylic sheet, an ABS (acrylonitrile-butadiene-styrene) sheet, a polystyrene sheet, an AS (acrylonitrile-styrene) sheet. , TPO (Thermo Plastic Olefin elastomer) sheet, TPU (Thermo Plastic Urethane elastomer), etc. are preferably used. The thickness of the sheet is 50 μm to 2000 μm, more preferably 100 μm to 1800 μm, and still more preferably 250 to 1500 μm. When the polyester film for molding of the present invention is used by being bonded to a base material for molding, the thickness is preferably less than 10 to 75 μm in terms of bonding properties and handleability, and further 12 to 50 μm. Preferably, it is most preferable if it is 15-40 micrometers.

  Moreover, in order to improve the adhesiveness with the base material for shaping | molding, it is preferable that the polyester film of this invention provides an adhesive layer. Although it does not specifically limit as an adhesive layer, A polyester type, a urethane type, an acrylic type, a chlorinated polypropylene type etc. are used preferably.

  Here, although the molding method of the decorative sheet for molding having the above-described configuration using the polyester film of the present invention will be specifically described, the molding method is not limited thereto.

  The polyester film for molding decoration of the present invention or the decorative sheet for molding is heated using a far-infrared heater at 150 to 400 ° C. so that the surface temperature is 50 to 230 ° C., and the mold is pushed up, By vacuuming, it is formed into a desired shape. In the case of molding with a strict magnification, deeper molding is possible by applying pressure air to the sheet and molding. The decorative sheet for molding thus formed is trimmed to form a molded member. The molded member may be used as it is. However, in order to give strength as a molded product, the above-described resin or the like may be injected into a depressed portion by pressing a mold. In this way, the molded member is completed.

  When using the polyester film of this invention for an in-mold shaping | molding use and an insert molding use, since a molded member can show the outstanding external appearance by laminating | stacking a decoration layer on the film surface, it is preferable. The decorative layer referred to here is a layer for adding decoration such as coloring, unevenness, pattern, wood grain, metal tone, pearl tone and the like. Although it does not specifically limit as a formation method of a decoration layer, For example, it can form by metal vapor deposition, printing, a coating, a transfer, etc.

  Here, the metal used for metal deposition is not particularly limited, but indium (melting point: 156 ° C), tin (melting point: 228 ° C), aluminum (melting point: 660 ° C), silver (melting point: 961). ° C), copper (melting point: 1083 ° C), zinc (melting point: 420 ° C), nickel (melting point: 1453 ° C), chromium (1857 ° C), titanium (1725 ° C), platinum (melting point: 1772 ° C), palladium (melting point) : 1552 ° C) or an alloy thereof, but it is preferable to use a metal having a melting point of 150 to 400 ° C. 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. The melting point of a particularly preferable metal compound is 150 to 300 ° C. Although it does not specifically limit as a metal compound whose melting | fusing point is 150-400 degreeC, Indium (157 degreeC) and tin (232 degreeC) are preferable, and it is preferable to use indium especially at the point of metallic luster and a color tone. it can.

  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 further improve the adhesion between the polyester film and the vapor deposition layer, the surface of the film may be pretreated by a method such as a corona discharge treatment or an anchor coating agent. 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 polyester film of the present invention has excellent moldability, and can easily form a molded part following the mold in thermoforming such as vacuum and pressure forming, so in-mold molding, insert molding, transfer foil, It is preferably used for molding applications such as molding protective films. For this reason, it is related with the polyester film used suitably for shaping | molding member uses, such as a building material, a motor vehicle part, a mobile phone, and an electrical appliance.

  Hereinafter, the present invention will be described in detail by way of examples. The characteristics were measured and evaluated by the following methods.

(1) It measured using melting | fusing point differential scanning calorimeter (Seiko Denshi Kogyo make, RDC220). Using 5 mg of a polyester film as a sample, the endothermic peak temperature when the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min was defined 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) Haze Based on JIS K 7105 (1985), film haze was measured using a haze meter (HGM-2GP manufactured by Suga Test Instruments Co., Ltd.). The measurement was performed at three arbitrary locations, and the average value was adopted.

(3) The layer thickness film was embedded in an epoxy resin, and the film cross section was cut out with a microtome. The cross section was observed with a transmission electron microscope (TEM H7100, manufactured by Hitachi, Ltd.) at a magnification of 5000 times, and the thickness ratio of each layer was determined. The thickness of each layer was calculated from the obtained lamination ratio and the above-described film thickness.

(4) The cross section of the average particle size film of the organic particles is observed at a magnification of 10,000 using a transmission electron microscope (TEM H7100, manufactured by Hitachi, Ltd.), and the image of the particles is processed with an image analyzer. The number average diameter D obtained by performing the following numerical processing with the number of particles of 1000 with different observation locations was defined as the average particle size.
D = ΣDi / N (Di: equivalent circle diameter of particles, N: number of particles)
(5) Contained particle concentration 10 g of a biaxially stretched polyester film was dissolved in 100 g of orthochlorophenol, and the particles were centrifuged from the polyester. Measure the mass of the separated particles,
(Particle concentration) = (particle mass) / (total film mass) × 100
The particle concentration was determined. In addition, evaluation was performed 5 times and the average value was made into particle concentration.
(6) Composition of polyester film The 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 is determined using ¹ H-NMR and ¹³ C-NMR. It can be quantified. In the case of a laminated film, the components constituting each layer can be collected and evaluated by scraping each layer of the film according to the laminated thickness. In addition, about the laminated | multilayer film of this invention, the composition was computed by calculation from the mixing ratio at the time of film manufacture.
(7) Plane orientation coefficient Using sodium D line (wavelength 589 nm) as a light source and using an Abbe refractometer, the refractive index in the longitudinal direction of the film (n _MD ), the refractive index in the width direction (n _TD ), the refraction in the thickness direction The ratio (n _ZD ) was measured, and the plane orientation coefficient (fn) was calculated from the following formula.
fn = (n _MD + n _TD ) / 2-n _ZD
(8) Centerline average roughness Using an ultradeep shape measuring microscope VK-8500 (Keyence), the two-dimensional line roughness of the film surface was measured and calculated from the data. The measurement sample used was a sample of five 5 cm × 5 cm samples in the width direction (25 cm) of the film. About each sample, six places were extracted from the film edge at equal intervals, and the measurement was performed (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.

  The average line center roughness after stretching 1.2 times each at 200 ° C. in the film longitudinal direction and the width direction is 100 using a film stretcher heated to 200 ° C. (manufactured by Toyo Seiki Seisakusho). A film cut into a size of × 100 mm was set, and after preheating for 20 seconds, the film was stretched by simultaneous biaxial stretching at a rate of 2000% / min. . For each sample, 10 locations were extracted and the average value was taken for each sample.

(9) Static friction coefficient (μs), dynamic friction coefficient (μd)
According to ASTM-D-1894B-63, a static friction coefficient (μs) and a dynamic friction coefficient (μd) were measured using a slip tester.

(10) The stress film at 100% elongation was cut into a rectangular shape having a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction to obtain a sample. 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 500 mm / min. For the measurement, a film sample was set in a constant temperature layer set in advance at 150 ° C., and a tensile test was performed after preheating for 60 seconds. The load applied to the film when the sample was stretched 100% was read, and the value obtained by dividing the load by the cross-sectional area (film thickness × 10 mm) of the sample before the test was defined as the stress at 100% stretch (F100 value). In addition, the measurement was performed 5 times for each sample and each direction, and the average value was evaluated.

(11) Formability To the polyester film of the present invention, an adhesive obtained by mixing 20: 1: 20 of an adhesive AD503 manufactured by Toyo Morton Co., Ltd., a curing agent CAT10, and ethyl acetate was applied as an adhesive layer. An ABS sheet having a thickness of 1500 μm was bonded to the adhesive layer, and heat-pressed (80 ° C., 0.1 MPa, 3 m / min) using a laminator to prepare a decorative sheet for molding. The decorative sheet for molding is heated using a far-infrared heater at 400 ° C. so that the surface temperature becomes 150 ° C., and vacuum forming is performed along a mold (bottom diameter 50 mm) heated to 70 ° C. went. 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).
S: Molding was possible at a drawing ratio of 0.5 or more.
A: Molding was possible with a drawing ratio of 0.4 to less than 0.5.
B: Molding was possible with a drawing ratio of 0.3 to less than 0.4.
C: Low followability and could not be formed into a shape with a drawing ratio of 0.3.

(12) Indium was sputtered to a thickness of 100 nm on one surface of the metal-like evaluation film, and each sample was visually observed from the non-metal layer surface, whereby the sharpness of the film was evaluated and determined according to the following criteria.
S: Very high brightness and a clean metallic tone were observed.
A: Although there was a part where the glitter was slightly low, a clean metallic tone was observed.
B: A metallic tone with slightly low brightness was observed.
C: White spots were observed, the glitter feeling was low, and the metallic tone was inferior.

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

(PET)
0.04 parts by mass of manganese acetate is added to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, the temperature is gradually raised, and finally transesterification is performed while distilling methanol at 220 ° C. It was. Next, 0.025 parts by mass of 85% phosphoric acid aqueous solution and 0.02 parts by mass of germanium dioxide were added, and a polycondensation reaction was performed at 290 ° C. under a reduced pressure of 1 hPa, the intrinsic viscosity was 0.65, and by-produced diethylene glycol 2 A mol% copolymerized polyethylene 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 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)
Copolymerized polyester (Eastman PETG6763 manufactured by Eastman Chemical Co.) copolymerized with 30 mol% of 1,4-cyclohexanedimethanol and PET were mixed at a mass ratio of 70:30, and 280 using a vent type twin screw extruder. It knead | mixed at (degreeC) and obtained 1, 4- cyclohexane dimethanol 21mol% copolymerization polyethylene terephthalate resin.

(PET-I)
To a mixture of 82.5 parts by weight of dimethyl terephthalate, 17.5 parts by weight of dimethyl isophthalate 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 were added. Then, the temperature was gradually raised, and finally transesterification was performed while distilling methanol at 220 ° C. Subsequently, 0.020 parts 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. The reaction system is gradually depressurized while being heated in the polymerization kettle, and the polycondensation reaction is performed at 287 ° C. under a reduced pressure of 1 hPa, and the intrinsic viscosity is 0.7 and by-product diethylene glycol is copolymerized by 2 mol%. An acid 17.5 mol% copolymerized polyethylene terephthalate resin was obtained.

(Particle M1)
Add 0.09 parts by mass of calcium acetate to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, gradually increase the temperature, and finally conduct a transesterification reaction while distilling methanol at 220 ° C. It was. Next, divinylbenzene / styrene (20/80) having a thermal decomposition temperature of 400 ° C., an average particle diameter of 2 μm, and a refractive index of 1.62 dispersed as 0.2 parts by mass of trimethyl phosphate and a 5% by mass ethylene glycol slurry. ) Polyethylene terephthalate particles copolymerized by addition of cross-linked particles to 21% by mass, polycondensation reaction under reduced pressure of 290 ° C. and 1 hPa, intrinsic viscosity of 0.65 and by-produced diethylene glycol 2 mol% Got the master.

(Particle M2)
In the same manner as the particles M1, it contained 2% by mass of divinylbenzene / styrene / methyl methacrylate (15 / 84.5 / 0.5) crosslinked particles having an average particle diameter of 1.5 μm and a refractive index of 1.6. A polyethylene terephthalate particle master copolymerized with 2 mol% of diethylene glycol by-product having a viscosity of 0.65 was obtained.

(Particle M3)
In the same manner as the particles M1, the intrinsic viscosity was 0.65 containing 2% by mass of divinylbenzene / styrene / methyl methacrylate (30/67/3) crosslinked particles having an average particle diameter of 0.8 μm and a refractive index of 1.58. A polyethylene terephthalate particle master copolymerized with 2 mol% of diethylene glycol as a by-product was obtained.

(Particle M4)
In the same manner as the particles M1, an intrinsic viscosity of 0.65 containing 2% by mass of divinylbenzene / styrene / diethyl ether (12/83/5) crosslinked particles having an average particle diameter of 0.4 μm and a refractive index of 1.52; A polyethylene terephthalate particle master copolymerized with 2 mol% of diethylene glycol as a by-product was obtained.

(Particle M5)
In the same manner as the particles M1, the intrinsic viscosity was 0.65 containing 2% by mass of divinylbenzene / styrene / methyl methacrylate (5/80/15) crosslinked particles having an average particle diameter of 0.3 μm and a refractive index of 1.56. A polyethylene terephthalate particle master copolymerized with 2 mol% of diethylene glycol as a by-product was obtained.

(Particle M6)
In the same manner as the particles M1, containing 2% by mass of styrene / titanium oxide (85/15) crosslinked particles having an average particle diameter of 1 μm and a refractive index of 1.65, an intrinsic viscosity of 0.65 and by-produced diethylene glycol of 2 mol% A copolymerized polyethylene terephthalate particle master was obtained.

(Particle M7)
In the same manner as the particles M1, the intrinsic viscosity was 0.65 containing 2% by mass of styrene / diethyl ether (90/10) crosslinked particles having an average particle diameter of 0.35 μm and a refractive index of 1.51, and by-produced diethylene glycol 2 A polyethylene terephthalate particle master copolymerized with mol% was obtained.

(Particle M8)
In the same manner as the particles M1, containing 2% by mass of styrene / titanium oxide (88/12) crosslinked particles having an average particle diameter of 2 μm and a refractive index of 1.63, an intrinsic viscosity of 0.65 and by-produced diethylene glycol of 2 mol% A copolymerized polyethylene terephthalate particle master was obtained.

(Particle M9)
In the same manner as the particle M1, a polyethylene terephthalate particle master containing 2% by weight of wet silica agglomerated particles having an average particle diameter of 2 μm and a refractive index of 1.42 and having an intrinsic viscosity of 0.65 and 2 mol% of diethylene glycol as a by-product is copolymerized. Got.

(Particle M10)
In the same manner as the particle M1, containing 2% by mass of divinylbenzene / styrene / titanium oxide (50/32/18) crosslinked particles having an average particle diameter of 3 μm and a refractive index of 1.67, an intrinsic viscosity of 0.65 and a by-product A polyethylene terephthalate particle master copolymerized with 2 mol% of diethylene glycol was obtained.

(Particle M11)
In the same manner as the particles M1, the intrinsic viscosity was 0.65 containing 2% by mass of distyrene / diethyl ether (88/12) crosslinked particles having an average particle diameter of 0.7 μm and a refractive index of 1.48, and by-produced diethylene glycol 2 A polyethylene terephthalate particle master copolymerized with mol% was obtained.

Example 1
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PBT, particles M1 and particles M5 were mixed at a mass ratio of 24: 50: 20: 1: 5. As polyester B which comprises B layer, PET, PET-G, and PBT were mixed and used by mass ratio 30:50:20 ratio.

  Each mixed polyester resin was individually dried in a vacuum dryer at 180 ° C. for 4 hours, and after sufficiently removing moisture, supplied to separate single screw extruders, melted at 280 ° C., and filtered through separate paths. After removing the foreign matter and leveling the amount of extrusion through the gear pump, A layer / B layer / A layer (see the table for lamination thickness ratio) in the feed block installed on the top of the T die After the lamination, 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 was raised with a heated roll, finally stretched 3.1 times in the longitudinal direction at a film temperature of 95 ° C., and immediately cooled with a metal roll whose temperature was controlled at 40 ° C. . Next, the film was stretched 3.1 times in the width direction at a preheating temperature of 70 ° C. and a stretching temperature of 100 ° C. with a tenter-type transverse stretching machine, and the temperature was kept at 235 ° C. for 5 seconds while relaxing 3% in the width direction. Heat treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 25 μm.

(Example 2)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PBT, particles M2 and particles M5 were mixed at a mass ratio of 16: 60: 20: 1: 3. As polyester B constituting the B layer, PET, PET-G and PBT were mixed and used at a mass ratio of 20:60:20.
A biaxially oriented polyester film having a film thickness of 15 μm was obtained in the same manner as in Example 1 except that the heat treatment temperature was 230 ° C.

(Example 3)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PBT, particles M3 and particles M5 were mixed at a mass ratio of 43: 30: 20: 2: 5. As polyester B constituting the B layer, PET, PET-G and PBT were mixed and used at a mass ratio of 50:30:20.
A biaxially oriented polyester film having a film thickness of 20 μm was obtained in the same manner as in Example 1 except that the heat treatment temperature was 225 ° C.

Example 4
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PBT, particles M8 and particles M4 were mixed at a mass ratio of 63: 30: 2: 5. As polyester B constituting the B layer, PET and PBT were mixed and used at a mass ratio of 70:30.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 15 μm was obtained.

(Example 5)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, particles M6 and particles M7 were mixed at a mass ratio of 70: 20: 3: 7. As polyester B constituting the B layer, PET and PET-G were mixed and used at a mass ratio of 80:20.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 13.6 μm was obtained.

(Example 6)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET-I, PPT, particles M2 and particles M7 were mixed at a mass ratio of 74: 20: 1: 5. As polyester B constituting the B layer, PET-I and PPT were mixed and used at a mass ratio of 80:20.
A biaxially oriented polyester film having a film thickness of 20 μm was obtained in the same manner as in Example 1 except that the heat treatment temperature was 200 ° C.

(Example 7)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PBT, and particles M8 were mixed at a mass ratio of 48: 10: 20: 22. As polyester B constituting the B layer, PET, PET-G, and PBT were mixed and used at a mass ratio of 70:10:20.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 25 μm was obtained.

(Example 8)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PPT, and particles M4 were mixed at a mass ratio of 45: 20: 30: 5. As polyester B constituting the B layer, PET, PET-G and PPT were mixed and used at a mass ratio of 50:20:30.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 22 μm was obtained.

Example 9
A two-layer laminated film of A layer / B layer was obtained. As polyester A constituting the A layer, PET, PET-I, PBT, and particles M3 were mixed at a mass ratio of 70: 10: 10: 10. As polyester B constituting the B layer, PET, PET-I and PBT were mixed and used at a mass ratio of 80:10:10.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 41 μm was obtained.

(Example 10)
It was set as the single layer film. As polyester A constituting the A layer, PET, PET-I, particles M5 and particles M9 were mixed and used at a mass ratio of 53: 20: 25: 2. Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 25 μm was obtained.

(Comparative Example 1)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-G, PPT, and particles M10 were mixed at a mass ratio of 40: 25: 30: 5. As polyester B constituting the B layer, PET, PET-G, and PPT were mixed and used at a mass ratio of 45:25:30.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 25 μm was obtained.

(Comparative Example 2)
A three-layer laminated film of A layer / B layer / A layer was obtained. As polyester A constituting the A layer, PET, PET-I, PBT, and particles M11 were mixed at a mass ratio of 55: 10: 30: 5. As polyester B constituting the B layer, PET, PET-I, and PBT were mixed and used at a mass ratio of 60:10:30.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 40 μm was obtained.

(Comparative Example 3)
A single layer film was formed. As polyester A constituting the A layer, PET and PBT were mixed and used at a mass ratio of 80:20. Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 20 μm was obtained.

(Comparative Example 4)
A single layer film was formed. As polyester A constituting the A layer, PET-G, particles M8, and particles M7 were mixed and used at a mass ratio of 40:30:30. Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 15 μm was obtained.

(Comparative Example 5)
A two-layer laminated film of A layer / B layer was obtained. As polyester A constituting the A layer, PET, PET-I, particles M2, and particles M4 were mixed at a mass ratio of 66: 10: 12: 12. As polyester B constituting the B layer, PET and PET-I were mixed and used at a mass ratio of 90:10.
Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a film thickness of 25 μm was obtained.

The abbreviations in the table are as follows.
DVB: divinylbenzene St: styrene MMA: methyl methacrylate DEE: diethyl ether TiO ₂ : titanium oxide

  The present invention relates to a polyester film for molding, and is particularly excellent in moldability, transparency and processability, so that various moldings such as insert molding and in-mold molding are possible, and the appearance after molding is also excellent. Therefore, it is suitably used for molding materials such as building materials, automobile parts, mobile phones, and electrical products.

Claims (4)

100% by mass for the entire polyester film, 0.001 to 1% by mass of organic particles (A) having a refractive index of 1.5 to 1.65, and for molding that satisfies the following formulas (1) and (2) Polyester film.
1 ≦ F100 _MD ≦ 50 (1)
1 ≦ F100 _TD ≦ 50 (2)
However, F100 _MD : Stress at 100% elongation in the longitudinal direction at 150 ° C. (unit: MPa)
F100 _TD : Stress at 100% elongation in the width direction at 150 ° C. (unit: MPa) The organic particle (a1) having a particle size of 0.01 to less than 0.5 μm and the organic particle (a2) having a particle size of less than 0.5 to 3 μm are contained as the organic particle (A). 2. The molding polyester film according to 1. The polyester film for molding according to claim 1 or 2, wherein the film is a laminated film composed of at least two layers, and the layer thickness of at least one layer is less than 0.1 to 3 µm. The polyester film for molding according to any one of claims 1 to 3, which has an average line center roughness of less than 1 to 20 nm after being stretched 1.2 times in the film longitudinal direction and the width direction at 200 ° C.