JP2008095084A - Polyester film for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester film for molding, which is excellent in moldability at a low temperature and at low pressure, in transparency, solvent resistance and heat resistance, does not cause blocking and breakage of the film, when the long film wound up in a roll-like form is unwound, and little causes formation of deposits and deterioration in transparency under high temperature environments, when the film is processed or molded, or after the film is molded. <P>SOLUTION: This biaxially oriented film comprising a copolyester is characterized in that (1) stress in the longitudinal and lateral directions of the film on 100% extension is 40 to 300 MPa at 25°C and 1 to 100 MPa at 100°C; (2) a thermal shrinkage rate in the longitudinal and lateral directions of the film at 150°C is 0.01 to 5.0%; (3) haze is 0.1 to 3.0%; (4) the surface roughness (Ra) of the film on at least one side is 0.005 to 0.030 μm; (5) a planar orientation degree is ≤0.095; and (6) the increase of the haze is ≤0.3, after the film is thermally treated at 170°C for 10 min. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is excellent in moldability, transparency, solvent resistance, heat resistance at low temperature and low pressure, and blocking or breaking of the film when unwinding a long film wound up in a roll shape. For generation of various portable equipment casings, home appliances, and automobile nameplates that do not occur and have little deposits, low transparency, and low environmental impact during processing and molding of films and in high-temperature environments after molding. Alternatively, the present invention relates to a molding polyester film suitable as a building material member. In addition, the present invention relates to a polyester film for molding that is excellent in light resistance suitable for applications used outdoors (members for automobile exteriors or building materials).

  Conventionally, as a sheet | seat for shaping | molding, a polyvinyl chloride film is typical and has been preferably used at points, such as workability. On the other hand, the film has problems such as generation of toxic gas when the film burns due to fire and the like, bleed-out of the plasticizer, and the recent demand for environmental resistance has demanded new materials with low environmental impact. ing.

In order to satisfy the above requirements, unstretched sheets made of polyester, polycarbonate and acrylic resin have been used in a wide range of fields as non-chlorine materials. In particular, unstretched sheets made of a polyester resin are attracting attention because they have good mechanical properties and transparency, and are excellent in economic efficiency. For example, an unstretched polyester-based sheet comprising substantially non-crystalline polyester-based resin in which about 30 mol% of ethylene glycol component in polyethylene terephthalate is substituted with 1,4-cyclohexanedimethanol is disclosed ( For example, see Patent Documents 1 to 5).
Japanese Patent Laid-Open No. 9-156267 JP 2001-71669 A JP 2001-80251 A JP 2001-129951 A JP 2002-249652 A

  The above-mentioned unstretched polyester sheet satisfies market demands regarding moldability and laminate suitability, but because it is an unstretched sheet, it does not have sufficient heat resistance and solvent resistance and satisfies high market demands. It has not yet reached.

As a method for solving the above problems, a method using a biaxially stretched polyethylene terephthalate film is disclosed (for example, see Patent Documents 6 to 9).
JP-A-9-187903 JP-A-10-296937 Japanese Patent Laid-Open No. 11-10816 JP-A-11-268215

  However, although the heat resistance and solvent resistance are improved, the above method has insufficient moldability and does not satisfy the market demand in terms of the balance of overall quality.

As a method for solving the above-described problem, a method for specifying a stress at 100% elongation of a film is disclosed (for example, see Patent Documents 10 and 11).
JP-A-2-204020 JP 2001-347565 A

  Although this method has improved moldability as compared with the above-described method, it does not reach a level that can sufficiently meet the high demands of the market regarding moldability. In particular, there remains a problem in moldability that can be adapted to lowering the molding temperature and the finished quality of the obtained molded product.

The present inventors have studied the solution of the above-mentioned problem, and have already developed a method of improving the above-mentioned problem by specifying a 100% elongation stress of the film using a copolymer polyester resin having the specified composition as a raw material. (For example, refer to Patent Document 11).
Japanese Patent Application Laid-Open No. 2004-075713

  With this method, in the mold molding method with high molding pressure at the time of molding, it can greatly improve the moldability that can meet the market demand and adapt to the lowering of the molding temperature and the finished product obtained. it can. However, in the case of a molding method having a low molding pressure at the time of molding, such as a compressed air molding method or a vacuum molding method, which has become increasingly demanding in the market, it is desired to further improve the finish of the molded product.

In addition, as a polyester film for molding that can be applied to a pressure molding method or a vacuum molding method, which is a molding method with a low molding pressure at the time of molding, it is composed of a biaxially stretched polyester film containing a copolymerized polyester, and the film at 25 ° C. and 100 ° C. The present inventors have proposed a polyester film for molding having a specific range of stress at 100% elongation, storage elastic modulus (E ′) at 100 ° C. and 180 ° C., and thermal deformation rate at 175 ° C. (for example, Patent Document 13) reference). However, it was found that blocking and tearing are likely to occur when the film is continuously produced and wound into a roll, and then the film is unwound and processed. Therefore, it is desired to further improve the productivity and the stability of quality during post-processing such as deposition or sputtering of metal or metal oxide on a film or printing.
JP-A-2005-290354

  In addition, precipitates resulting from the cyclic trimer are generated due to heat during processing such as printing or vapor deposition on the film surface, and the quality of the printing surface or vapor deposition surface may be lowered. Further, when the film is molded, the mold is contaminated, the frequency of cleaning is increased, and the productivity is lowered. Moreover, when the obtained molded product was used at a high temperature after the film was molded, there was a problem that the transparency was lowered. As described above, there is a strong demand from the market not only for moldability but also for improving precipitates and transparency deterioration due to heat not only in film processing and molding, but also in a high-temperature environment after molding.

  The object of the present invention is to solve the above-mentioned conventional problems, and is excellent in moldability, transparency, solvent resistance and heat resistance under low temperature and low pressure, and wound in a roll shape. When unwinding a long film, blocking and tearing of the film do not occur, and during processing and molding of the film, there are few precipitates in the high-temperature environment after molding, the decrease in transparency is small, and the environment An object of the present invention is to provide a molding polyester film that is suitable as a casing for various portable devices, home appliances, automobile nameplates, or building material members having a low load.

  The polyester film for molding of the present invention capable of solving the above-mentioned problems has the following configuration.

  1st invention in this invention is a polyester film for shaping | molding which consists of a biaxially oriented polyester film containing copolyester, (1) 100% elongation stress in the longitudinal direction and the width direction of a film is 25 40 to 300 MPa at 100 ° C. and 1 to 100 MPa at 100 ° C., (2) the thermal shrinkage in the longitudinal direction and the width direction at 150 ° C. of 0.01 to 5.0%, and (3) haze of 0.1 to 0.1%. 3.0%, (4) surface roughness (Ra) of at least one side film is 0.005 to 0.030 μm, (5) plane orientation degree is 0.095 or less, (6) film at 170 ° C. for 10 minutes The polyester film for molding is characterized in that an increase in haze after heat treatment is 0.3% or less.

  According to a second invention, the copolymer polyester comprises (a) a copolymer polyester comprising an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol, or (b The polyester film for molding according to the first invention, which is a copolyester composed of an aromatic dicarboxylic acid component containing terephthalic acid and isophthalic acid and a glycol component containing ethylene glycol.

  According to a third invention, the polyester constituting the biaxially oriented polyester film further contains a 1,3-propanediol unit or a 1,4-butanediol unit as a glycol component. It is a polyester film for molding.

  4th invention is the polyester film for shaping | molding in any one of 1st-3rd invention, wherein melting | fusing point of a biaxially-oriented polyester film is 200-245 degreeC.

  The fifth invention is a polyester film for molding comprising a biaxially oriented polyester film as a base film, and a surface layer having a thickness of 0.01 to 5 μm laminated on one or both sides of the base film, The base film is a polyester film for molding according to any one of the first to fourth inventions, wherein the base film does not substantially contain particles, and the particles are contained only in the surface layer.

  A sixth invention is the polyester film for molding according to the fifth invention, characterized in that the surface layer is mainly composed of an adhesion modifying resin and particles.

  The molding polyester film of the present invention is excellent in moldability at the time of heat molding at a low temperature or low pressure, so that it can be applied to a wide variety of molding methods, and when used in a normal temperature atmosphere as a molded product, Excellent in shape stability (heat shrinkage characteristics, thickness unevenness), solvent resistance, heat resistance, and environmental impact is small. Further, when unwinding a long film wound up in a roll shape at the time of post-processing, blocking and tearing are unlikely to occur, resulting in excellent productivity.

  In addition, since the molding polyester film of the present invention has a small amount of cyclic trimer deposited on the film surface in a high temperature environment, when the film is heated, the transparency decreases and the cyclic trimer on the film surface. Migration is suppressed. Therefore, there is little generation of precipitates when processing such as printing or vapor deposition on the film, and there is little contamination of the mold during molding processing, and furthermore, high transparency can be maintained even when used at high temperatures. Have advantages. Therefore, since transparency is highly excellent, it is excellent in the design property at the time of providing a vapor deposition layer, a sputtering layer, or a printing layer at the time of post-processing. Therefore, it is suitable as a casing for various portable devices, home appliances, automobile nameplates or building materials.

  First, the technical significance of the physical properties defined by the moldable polyester film of the present invention will be described. Next, a method for producing the moldable polyester film of the present invention will be described.

(Technical meaning and significance of physical properties described in the present invention)
In the present invention, the stress at 100% elongation (F100) is a measure closely related to the moldability of the film. The reason why F100 is closely related to the moldability of the film is, for example, when a biaxially oriented polyester film is molded using a vacuum forming method, the film locally expands to 100% or more near the corner of the mold. There is a case. In a film having a high F100, extremely high stress is partially generated in such a locally stretched portion, and it is considered that the film breaks due to the stress concentration and the formability is lowered. On the other hand, a film having an F100 that is too small has good moldability, but only a very weak tension is generated in a portion that is uniformly stretched, such as a flat portion of a mold. It is thought that proper elongation cannot be obtained.

In the present invention, 100% elongation stress (F100 ₁₀₀ ) at 100 ° C. is used as a physical property related to the moldability corresponding to the temperature at the time of molding. In addition, when molding using a mold having irregularities and depressions, 100% at 25 ° C. is a physical property related to the moldability when the film before molding is lightly followed by the mold before molding. Elongation stress (F100 ₂₅ ) is used.

The polyester film for molding in the present invention has a stress at 100% elongation (F100 ₂₅ ) at 25 ° C. in the longitudinal direction and the width direction of the film of 30 to 300 MPa.

F100 ₂₅ in the longitudinal direction and the width direction of the film is 40 to 300 MPa, and the lower limit is preferably 50 MPa, more preferably 60 MPa. The upper limit is preferably 250 MPa, more preferably 200 MPa, and still more preferably 180 MPa. When F100 ₂₅ is less than 40 MPa, when the roll-shaped film is pulled and unwound, the film is stretched or torn, resulting in poor workability. On the other hand, when F100 ₂₅ exceeds 300 MPa, the moldability becomes poor. In particular, when molding is performed using a mold having irregularities and depressions, a film before molding may be followed by lightly following those molds in advance. In such a case, it is difficult to mold the film, and the finished product may have poor design properties.

In the molding polyester film of the present invention, it is important that the 100% elongation stress (F100 ₁₀₀ ) at 100 ° C. in the longitudinal direction and the width direction of the film is _{1 to 100} MPa.

The upper limit of F100 ₁₀₀ in the longitudinal direction and the width direction of the film is preferably 90 MPa, more preferably 80 MPa, and particularly preferably 70 MPa from the viewpoint of moldability. On the other hand, the lower limit of F100 ₁₀₀ is preferably 5 MPa, more preferably 10 MPa, and particularly preferably 20 MPa from the viewpoint of elasticity and shape stability when using a molded product.

In the film of the present invention, the thermal shrinkage in the longitudinal direction and the width direction at 150 ° C. is 0.01 to 5.0%. The lower limit value of the heat shrinkage rate at 150 ° C. is preferably 0.1%, more preferably 0.5%. On the other hand, the upper limit value of the heat shrinkage rate at 150 ° C. is preferably 4.5%, more preferably 4.1%, and still more preferably 3.2%. Even when a biaxially stretched polyester film for molding having a thermal shrinkage of less than 0.01% in the longitudinal and width direction films at 150 ° C. is produced, there is no significant difference in practical effects, and productivity is improved. Since it is very low, there is no necessity to make the heat shrinkage rate at 150 ° C. less than 0.01%. On the other hand, if the thermal shrinkage rate of the film in the longitudinal direction and the width direction at 150 ° C. exceeds 5.0%, the film is likely to be deformed in a post-processing step that requires heat such as vapor deposition, sputtering or printing, and after post-processing. The appearance and design of the film will be poor.

In the present invention, the haze of the film is 0.1 to 3.0%. The lower limit of haze is preferably 0.3%, more preferably 0.5%. On the other hand, the upper limit of haze is preferably 2.5%, more preferably 2.0%. A film having a haze of less than 0.1% is poor in slipperiness, so that it is difficult to produce it on an industrial scale with normal productivity. On the other hand, when the haze of the film exceeds 3.0%, when the vapor deposition or sputtering surface of the metal or the printed surface is viewed from the back surface of the film, the metal or the printed surface looks dull, resulting in poor design. In addition, it is difficult to obtain a film having a haze of 2.0% or less by a method for forming irregularities on the film surface by incorporating particles in the film, which is generally performed for improving handling properties in the film. .

In the present invention, the surface roughness (Ra) of at least one film is 0.005 to 0.030 μm. The lower limit of Ra is preferably 0.006 μm, and more preferably 0.007 μm. On the other hand, the upper limit value of Ra is preferably 0.025 μm, more preferably 0.015 μm. As the Ra of at least one side of the film becomes smaller, it becomes difficult to wind the film, and the frequency of occurrence of blocking or breaking of the film increases when the film once wound up in a roll shape is unwound. On the other hand, when Ra exceeds 0.03 μm, the protrusion becomes a defect in a post-processing step such as vapor deposition, sputtering, or printing, and the design property is deteriorated.

  In the present invention, the degree of plane orientation (ΔP) of the film is also a physical property related to moldability, and the higher the degree of plane orientation, the more the molecular chains are arranged in the plane direction and the moldability is lowered. In the present invention, the upper limit of the degree of plane orientation of the film is required to be 0.095 or less, and 0.090 is more preferable. Further, the smaller the degree of plane orientation, the better the moldability, but the strength of the film is lowered, and the flatness such as thickness unevenness tends to deteriorate. Therefore, the lower limit of the degree of plane orientation is preferably 0.001, more preferably 0.01, and particularly preferably 0.04.

  In the molding polyester film of the present invention, it is important that the increase in haze after heating at 170 ° C. for 10 minutes is 0.30% or less, preferably 0.25% or less, particularly preferably. It is 0.20% or less. It is most preferable that the amount and haze of the cyclic trimer on the film surface do not change even when the film is subjected to the above heat treatment. However, in order to make the change in the characteristics zero, an extremely high level of technology is required. However, in practice, if it can be managed within the above range, it can be used without any problem.

  When the increase in haze after heating the film at 170 ° C. for 10 minutes exceeds 0.30%, when processing with heat such as printing or vapor deposition is performed, when molding at high temperature or under reduced pressure, When used in the above, the transfer of the cyclic trimer to the film surface is increased, and a decrease in transparency and a decrease in quality due to precipitates are observed.

Further, molding the polyester film of the present invention preferably has a cyclic trimer of the film surface is 0.20 mg / ^{m 2} or less, and more preferably not more than 0.18 mg / ^{m 2,} particularly preferably 0. 16 mg / m ² or less. When the cyclic trimer on the surface of the film exceeds 0.20 mg / m ² , adhesion inhibition and defects occur when a functional layer or a functional film having various functions is laminated on the film.

In the molding polyester film of the present invention, the cyclic trimer on the film surface when the polyester film is heated at 170 ° C. for 10 minutes is preferably 0.9 mg / m ² or less, more preferably 0.6 mg. / M ² or less, particularly preferably 0.3 mg / m ² .

(Concept of the present invention)
This application is an improved invention of Patent Document 12 described in the prior art.
A polyester film obtained by using a copolymer polyester containing 5 to 50 mol% of a copolymer component as a raw material as in the present invention has a slower crystallization rate and lower crystallinity than a polyethylene terephthalate film or the like. In order to reduce the degree of plane orientation and the thermal shrinkage at 150 ° C., when the method of heat treatment at a higher temperature than usual described in Patent Document 12 is used, the heat treatment is suddenly performed at a high temperature after completion of stretching. In the heat treatment zone, the mobility of molecules constituting the material having low crystallinity is increased. Therefore, the surface protrusions formed by the bulging of the particles (particles in the biaxially oriented film or particles in the coating layer) in the stretching process are buried again in the heat treatment zone, so that the surface roughness is sufficient. Can't get. Therefore, there is a problem that haze deteriorates when the amount of particles added is increased more than necessary in order to prevent the blocking and tearing when winding the film neatly and winding the film wound up in a roll shape. .

  In the present invention, the above-mentioned problems have been solved by using a suitable method in which the heat treatment zone has two stages (or more) and the first stage heat treatment temperature TS1 and the second stage heat treatment temperature TS2 are controlled within a specific range. It is. This mechanism is considered as follows.

  In the first heat treatment zone, the crystallization of the film is promoted to some extent before the particles are buried inside the film, and even if the temperature is raised sufficiently in the second heat treatment zone, the molecular motion The properties are sufficiently lowered, and the film having a low thermal shrinkage rate can be obtained by further promoting the crystallinity while forming the projections on the surface. Moreover, it is not necessary to contain particles more than necessary from the viewpoint of transparency.

  Furthermore, at least one technique of reducing the content of the cyclic trimer in the raw material polyester resin or the technique for suppressing the regeneration of the cyclic trimer in the molten polyester resin in the melt extrusion process during film production is used. Thus, the content of the cyclic trimer in the film is reduced. Therefore, the film can suppress an increase in haze caused by the cyclic trimer even in a high temperature environment (for example, at 170 ° C. for 10 minutes), and can maintain high transparency.

(Preferable production method of film)
The polyester film for molding of the present invention uses a copolymerized polyester as a raw material. Examples of the copolyester include (a) a copolyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol, or (b) terephthalic acid and isophthalic acid. A copolyester composed of an aromatic dicarboxylic acid component containing an acid and a glycol component containing ethylene glycol is preferred. Moreover, it is preferable from the point which further improves the moldability that the polyester which comprises a biaxially-oriented polyester film further contains a 1, 3- propanediol unit or a 1, 4- butanediol unit as a glycol component.

  In the present invention, as the film raw material, any method of copolymerized polyester alone, one or more homopolyesters or a blend of copolymerized polyesters, or a combination of homopolyester and copolymerized polyester is possible. Among these, the blending method is preferable from the viewpoint of suppressing the lowering of the melting point.

  When using a copolymer polyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol as the copolymer polyester, the aromatic dicarboxylic acid component is Terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or ester-forming derivatives thereof are suitable, and the amount of terephthalic acid and / or naphthalenedicarboxylic acid component relative to the total dicarboxylic acid component is 70 mol% or more, preferably 85 mol% or more. Particularly preferred is 95 mol% or more, and particularly preferred is 100 mol%.

  Examples of branched aliphatic glycols include neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and the like. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol and tricyclodecane dimethylol.

  Among these, neopentyl glycol and 1,4-cyclohexanedimethanol are particularly preferable. Furthermore, in the present invention, it is a more preferable embodiment that 1,3-propanediol or 1,4-butanediol is used as a copolymerization component in addition to the glycol component. Use of these glycols as a copolymerization component is suitable for imparting the above-mentioned properties, and is also excellent in transparency and heat resistance, and from the viewpoint of improving the adhesion with the adhesion modified layer. Is also preferable.

  When the copolymer polyester is composed of an aromatic dicarboxylic acid component containing terephthalic acid and isophthalic acid and a glycol component containing ethylene glycol, the amount of ethylene glycol is based on the total glycol component. It is 70 mol% or more, preferably 85 mol% or more, particularly preferably 95 mol% or more, and particularly preferably 100 mol%. As the glycol component other than ethylene glycol, the above-mentioned branched aliphatic glycol, alicyclic glycol, or diethylene glycol is preferable.

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

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

  The copolyester preferably has an intrinsic viscosity of 0.50 dl / g or more, more preferably 0.55 dl / g or more, and particularly preferably from the viewpoint of moldability, adhesion, and film formation stability. 60 dl / g or more. If the intrinsic viscosity is less than 0.50 dl / g, the moldability tends to decrease. In addition, when a filter for removing foreign substances is provided in the melt line, the upper limit of the intrinsic viscosity is preferably 1.0 dl / g from the viewpoint of ejection stability during extrusion of the molten resin.

  In the present invention, one or more homopolyesters or copolymerized polyesters are used as film raw materials, and these are blended to form a film, thereby maintaining the same flexibility as when only the copolymerized polyester is used. However, transparency and high melting point (heat resistance) can be realized. In addition, when only a high melting point homopolyester (for example, polyethylene terephthalate) is used, it is possible to realize a melting point (heat resistance) having no flexibility and practical problem while maintaining high transparency.

  Further, blending at least one or more of the copolymer polyester and a homopolyester other than polyethylene terephthalate (for example, polytetramethylene terephthalate or polybutylene terephthalate) and using it as a raw material for the molding polyester film of the present invention, It is further preferable from the viewpoint of moldability.

  The melting point of the polyester film is preferably 200 to 245 ° C. from the viewpoint of heat resistance and moldability. By controlling the type and composition of the polymer to be used and the film forming conditions within the range of the melting point, a balance between moldability and finish can be achieved, and a high-quality molded product can be produced economically. Here, the melting point is an endothermic peak temperature at the time of melting, which is detected at the time of primary temperature rise in so-called differential scanning calorimetry (DSC). The melting point was determined by measuring using a differential scanning calorimeter (manufactured by Mac Science, DSC3100S) at a heating rate of 20 ° C./min. The lower limit of the melting point is more preferably 210 ° C, particularly preferably 230 ° C. If the melting point is less than 200 ° C, the heat resistance tends to deteriorate. Therefore, it may become a problem when exposed to high temperature during molding or use of a molded product.

  The upper limit of the melting point is preferably higher from the viewpoint of heat resistance, but when the polyethylene terephthalate unit is the main component, the film having a melting point exceeding 250 ° C. tends to deteriorate moldability. In addition, transparency tends to deteriorate. Furthermore, in order to obtain high moldability and transparency, it is preferable to control the upper limit of the melting point to 245 ° C.

  Moreover, in order to improve handling properties, such as the slipperiness and winding property of a film, it is preferable to form an unevenness | corrugation on the film surface. As a method for forming irregularities on the film surface, a method of incorporating particles in the film is generally used.

  Examples of the particles include internal particles having an average particle size of 0.01 to 10 μm, external particles such as inorganic particles and / or organic particles. When particles having an average particle diameter exceeding 10 μm are used, defects in the film are liable to occur, and the design and transparency tend to deteriorate. On the other hand, in the case of particles having an average particle diameter of less than 0.01 μm, handling properties such as film slipperiness and winding property tend to be lowered. The lower limit of the average particle diameter of the particles is more preferably 0.10 μm, particularly preferably 0.50 μm, from the viewpoint of handling properties such as slipping property and winding property. On the other hand, the average particle diameter of the particles is more preferably 5 μm, particularly preferably 2 μm, from the viewpoint of transparency and reduction of film defects due to coarse protrusions.

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

  Examples of the external particles include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, hydroxyapatite and the like, and styrene, silicone, acrylic Organic particles or the like containing acids as constituent components can be used. Among these, inorganic particles such as dry, wet and dry colloidal silica and alumina and organic particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components are preferably used. Two or more of these internal particles, inorganic particles and / or organic particles may be used in combination as long as the characteristics defined in the present invention are not impaired.

  Furthermore, the content of the particles in the film is preferably in the range of 0.001 to 10% by mass. When the amount is less than 0.001% by mass, the handling property is likely to be deteriorated, for example, the slipperiness of the film is deteriorated or winding becomes difficult. On the other hand, if it exceeds 10% by mass, it tends to cause formation of coarse protrusions, deterioration of film forming property and transparency.

Moreover, since the particle | grains contained in a film generally differ in refractive index from polyester, it becomes a factor which reduces the transparency of a film. Molded products are films to improve design
In many cases, the film surface is printed before molding. Since such a printing layer is often applied to the back side of a molding film, it is desired that the transparency of the film is high from the viewpoint of printing clarity.

  Therefore, in order to obtain a high degree of transparency while maintaining the handleability of the film, the particles are not substantially contained in the base film of the main layer, and the particles are only in the surface layer having a thickness of 0.01 to 5 μm. It is effective to use a laminated film having a laminated structure containing. The upper limit of the thickness of the surface layer is preferably 3 μm, particularly preferably 1 μm. In this case, the particles exemplified above can be used.

In the present invention, in order to adjust the haze of the film to 0.1 to 3.0%, the surface film having a thickness of 0.01 to 5 μm is formed without substantially including particles in the base film. Thus, a laminated structure in which particles are contained only in the surface layer is preferable. In addition, it is difficult to obtain a film having a haze of 3.0% or less only by incorporating particles in the film while maintaining handling properties.

Note that “substantially no particles are contained in the base film” as used above means, for example, in the case of inorganic particles, the content that is below the detection limit when inorganic elements are quantified by fluorescent X-ray analysis. means. This is because contaminants derived from foreign substances may be mixed without intentionally adding particles to the base film.
In order to obtain a film having a low haze, it is preferable that particles are not substantially contained in the base film, but particles may be added to the base film as long as they are 30 ppm or less.

  The thin surface layer can be formed by a coating method or a coextrusion method. Especially, in the case of the coating method, since the adhesiveness with a printing layer can also be improved by using the composition which consists of adhesiveness modification resin containing particle | grains as an application layer, it is a preferable method. As said adhesive property modification resin, resin which consists of at least 1 sort (s) chosen from polyester, a polyurethane, an acrylic polymer, and / or those copolymers is preferable.

  As the particles to be contained in the surface layer, the same particles as those described above can be used. Among the particles, silica particles, glass fillers, and silica-alumina composite oxide particles are particularly suitable from the viewpoint of transparency because the refractive index is relatively close to that of polyester.

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

  In order to impart other functions, the polyester film of the present invention can be made into a laminated structure by a known method using different types of polyester. Examples of the form of such a laminated film include a laminated form of an A / B two-type two-layer structure, a two-type three-layer structure of a B / A / B structure, and a three-type three-layer structure of C / A / B.

  It is important that the molding polyester film of the present invention is a biaxially stretched film. In the present invention, due to molecular orientation by biaxial stretching, the thermal deformation rate of the film under micro tension (initial load 49 mN) can be controlled within the range of the present invention, which is a disadvantage of the unstretched sheet. Solvent resistance and dimensional stability are improved. That is, it is one of the features of the present invention that the solvent resistance and heat resistance, which are defects of the unstretched sheet, are improved while maintaining the good formability of the unstretched sheet.

  As a suitable production method of the biaxially oriented polyester film, for example, after drying a polyester resin as necessary, it is supplied to a known melt extruder, extruded from a slit-shaped die into a sheet, and applied electrostatically. There is a method in which a non-stretched sheet (raw material) is obtained by tightly adhering to a casting drum by a method, and then biaxially stretching the unstretched sheet.

  As the biaxial stretching method, a method is employed in which an unstretched sheet is stretched and heat-treated in the longitudinal direction (MD) and width direction (TD) of the film to obtain a biaxially stretched film having a desired in-plane orientation degree. . Among these methods, in terms of film quality, the MD / TD method in which the film is stretched in the longitudinal direction and then stretched in the width direction, or the TD / MD method in which the film is stretched in the width direction and then stretched in the longitudinal direction. An axial stretching method and a simultaneous biaxial stretching method in which the longitudinal direction and the width direction are stretched almost simultaneously are desirable. In the case of the simultaneous biaxial stretching method, a tenter driven by a linear motor may be used. Furthermore, if necessary, a multistage stretching method in which stretching in the same direction is performed in multiple stages may be used.

  The film stretching ratio when biaxially stretching is preferably 1.6 to 4.2 times in the longitudinal direction and the width direction, particularly preferably 1.7 to 4.0 times. In this case, the stretching ratio in the longitudinal direction and the width direction may be either larger or the same ratio. More preferably, the stretching ratio in the longitudinal direction is 2.8 to 4.0 times, and the stretching ratio in the width direction is 3.0 to 4.5 times.

  As the stretching conditions for producing the molding polyester film of the present invention, for example, the following conditions are preferably employed.

  In the longitudinal stretching, it is more preferable that the stretching temperature is 50 to 110 ° C. and the stretching ratio is 1.6 to 4.0 times so that the subsequent lateral stretching can be performed smoothly.

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

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

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

  Such a phenomenon is likely to occur when the thickness of the film is 60 to 500 μm, and is particularly noticeable in a film having a thickness of 100 to 300 μm. Therefore, in the case of a film using the copolymerized polyester of the present invention, the stretching temperature in the transverse direction is preferably set as follows.

First, preheating temperature is performed in the range of +10 degreeC-+50 degreeC of the glass transition temperature at the time of measuring the mixture (original fabric) after extruding a film material with an extruder in DSC. Next, in the first half of the transverse stretching, the stretching temperature is preferably −20 ° C. to + 15 ° C. with respect to the preheating temperature. In the latter half of the transverse stretching, the stretching temperature is preferably 0 ° C. to −30 ° C. with respect to the stretching temperature of the first half, and particularly preferably in the range of −10 ° C. to −20 ° C. with respect to the stretching temperature of the first half. It is. By adopting such conditions, the first half of the transverse stretching is easy to stretch because the yield stress is small, and the second half is easily oriented. In addition, it is preferable that the draw ratio of a horizontal direction shall be 2.5 to 5.0 times. As a result, it is possible to obtain a film that satisfies F100 ₂₅ and F100 ₁₀₀ defined in the present invention.

Furthermore, the film is subjected to heat treatment (heat setting treatment) after biaxial stretching. This heat treatment condition is an important condition for achieving both haze and surface roughness, that is, slipperiness of the film. The stretched film is subsequently heat-treated in the tenter. In this case, it is important to perform the heat treatment in two or more stages. The first stage heat treatment temperature (TS1) is in the range of −5 ° C. to −30 ° C. of the second stage heat treatment temperature (TS2), the lower limit is preferably TS2-10 ° C., and the upper limit is preferably TS2-25 ° C. is there. The second stage heat treatment temperature (TS2) is carried out in the range of −5 ° C. to −35 ° C. of the melting point when the mixture (raw material) after extruding the film material with an extruder is measured by DSC described later. The lower limit value of TS2 is preferably a melting point of −10 ° C., and the upper limit value of TS2 is preferably a melting point of −30 ° C. An intermediate heat treatment zone can be provided between TS1 and TS2, and a heat treatment zone can be provided after TS2. In these cases, TS2 shows the highest heat treatment temperature. By taking such conditions, a film having a low haze and good sliding properties can be obtained.
The heat treatment may be either a tension heat treatment or a relaxation heat treatment. In order to lower the heat shrinkage rate, a relaxation heat treatment of 3 to 10% is preferable.

  The reason is considered as follows. A polyester film containing about 5 to 50 mol% of a copolymer component as in the present invention has a lower crystallization speed and lower crystallinity than a polyethylene terephthalate film. Therefore, when heat treatment is performed rapidly at a high temperature after the end of stretching, the mobility of molecules constituting the material having low crystallinity is increased in the heat treatment zone. Accordingly, the surface protrusion formed by the bulging of the particles (particles in the film and / or particles of the coating layer) in the stretching process is buried again in the heat treatment zone, so that sufficient surface roughness is obtained. I can't. Therefore, in order to wind up the film neatly, the content of the particles is increased beyond the necessary amount of the polyethylene terephthalate film, which causes a decrease in haze. On the other hand, if the temperature of TS2 is lower than a predetermined temperature, a film having a sufficiently low thermal shrinkage at 150 ° C. cannot be obtained.

  Therefore, taking the method of the present invention in which the heat treatment zone has two stages (or more) is that the crystallization of the film is promoted to some extent before the particles are buried in the TS1 and the TS2 zone is sufficient. Even when the temperature is increased, the molecular mobility is sufficiently lowered as compared with the state of the previous paragraph, and the film is further promoted in crystallinity with the surface protrusions formed, and a film having a low thermal shrinkage rate can be obtained. Moreover, the addition of more than necessary particles can be prevented.

  In general, as a means for lowering the degree of plane orientation, a method of lowering the draw ratio and a method of increasing the blending amount of the copolymer component are known, but the former method deteriorates the thickness unevenness of the film. This is not preferable because the melting point is lowered and the heat resistance is deteriorated. In the present invention, in order to reduce the plane orientation degree of the biaxially oriented polyester film and the thermal shrinkage at 150 ° C., heat setting is performed at a higher temperature than usual. The heat setting is preferably performed in the above-described heat treatment, particularly the second heat treatment.

  In the present invention, it is necessary to use a copolyester as a biaxially oriented polyester film, and since the melting point is lower than that of a homogeneous polymer, if the heat setting temperature is increased, the clip that holds the film in the transverse stretching step The film is fused and difficult to peel off. Therefore, it is important to sufficiently cool the vicinity of the clip when the clip releases the film at the tenter outlet. Specifically, in order to make it easy to peel the film and the clip, (1) a method of providing a heat shielding wall on the clip portion so that the clip is hardly heated, and (2) a method of adding a clip cooling mechanism to the tenter. (3) A method in which the cooling section after heat setting is set long in order to enhance the cooling capacity, and the entire film is sufficiently cooled. (4) The cooling efficiency is increased by increasing the length of the cooling section and the number of sections. It is preferable to employ a method of increasing the clip, and (5) a method of enhancing the cooling of the clip by using a type in which the return portion of the clip travels outside the furnace.

  Hereinafter, means for reducing the haze increase after heating the film at 170 ° C. for 10 minutes to 0.30% or less will be described.

  In order to increase the haze after heating the film at 170 ° C. for 10 minutes to 0.30% or less, it is preferable to control the content of the cyclic trimer in the polyester resin used as the film raw material to 5000 ppm or less. More preferably, it is controlled to 4500 ppm or less, particularly preferably 4000 ppm or less.

  As a suitable means for reducing the content of the cyclic trimer in the polyester resin, for example, there is a method of solid-phase polymerization of a polyester chip having an intrinsic viscosity of 0.40 to 0.60 dl / g. It is done. Moreover, the method of heat-processing the polyester resin of predetermined intrinsic viscosity on the conditions which an intrinsic viscosity does not change substantially in inert gas atmosphere or pressure reduction is also illustrated. Further, a method of extracting with a solvent that dissolves the cyclic trimer may be used.

  Moreover, in the melt extrusion process at the time of film manufacture, it is important to suppress the reproduction | regeneration of the cyclic trimer in the polyester resin of a molten state. In order to suppress the regeneration of the cyclic trimer in the molten polyester resin as much as possible, it is important to reduce the amount of the active polymerization catalyst remaining in the polyester resin as much as possible. As a typical means for reducing the amount of such an active polymerization catalyst, the following method may be mentioned.

  One means is a method of inactivating the polymerization catalyst by bringing the polyester used as the film material into contact with water.

  Examples of the method for deactivating the polycondensation catalyst in the polyester used as the film raw material include a water treatment method in which the polyester chip is contact-treated with water, water vapor or water vapor-containing gas after melt polycondensation or after solid phase polymerization.

  Examples of the water treatment method include a method of immersing in water and a method of applying water on the chip with a shower. The treatment time when performing the water treatment is preferably 5 minutes to 2 days, more preferably 10 minutes to 1 day, and particularly preferably 30 minutes to 10 hours. Moreover, the temperature of water is preferably 20 to 180 ° C, more preferably 40 to 150 ° C, and particularly preferably 50 to 120 ° C.

  Below, the suitable method for performing water treatment industrially is illustrated. Further, the water treatment method may be either a continuous method or a batch method, but the continuous method is preferred for industrial use.

  A silo-type treatment tank is used when water-treating polyester chips in a batch system. In other words, the polyester chip is received in a silo in a batch system to perform water treatment. In the case where the polyester chips are water-treated in a continuous manner, the polyester chips can be continuously or intermittently received in the tower-type treatment tank from the upper part and water-treated.

  Further, when the polyester chip and water vapor or water vapor-containing gas are contacted, the water vapor or water vapor containing gas or water vapor containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably granular polyethylene. A method in which granular polyethylene terephthalate and water vapor are brought into contact with each other by supplying or presenting water in an amount of 0.5 g or more as water vapor per 1 kg of terephthalate is preferable.

  The contact between the polyester chip and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours.

  Below, although the method of industrially performing contact processing with granular polyethylene terephthalate, water vapor, or water vapor containing gas is illustrated, it is not limited to this. The processing method may be either a continuous method or a batch method.

  When a polyester chip is contact-treated with water vapor in a batch system, a silo type processing apparatus can be used. That is, a polyester chip is received in a silo, and contact processing is performed by supplying water vapor or water vapor-containing gas in a batch manner.

  When the polyester chips are continuously contacted with water vapor, it is possible to continuously receive granular polyethylene terephthalate from the upper part in a tower-type processing device and continuously supply water vapor in parallel flow or countercurrent to contact with water vapor. .

  In the case of treatment with water or steam, the granular polyethylene terephthalate is drained with a draining device such as a vibrating screen or a Simon Carter as necessary, and transferred to the next drying step by a conveyor.

  The polyester chip that has been contact-treated with water or water vapor can be dried by a commonly used polyester drying process. As a continuous drying method, a hopper-type ventilation dryer in which polyester chips are supplied from the upper part and a drying gas is supplied from the lower part is suitable. Moreover, as a method of drying by a batch method, a dryer that dries while aeration gas is passed under atmospheric pressure is preferable.

  As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferable from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of polyester.

  Moreover, as means other than water treatment, it comprises a polyester resin used as a film raw material (hereinafter referred to as polyester resin (1)), mainly an aromatic dicarboxylic acid and an ethylene glycol component, and a phosphorus compound as a phosphorus element. Examples include a method in which a polycondensation catalyst depleted polyester resin containing 100 to 5000 ppm (hereinafter referred to as polyester resin (2)) is mixed and melt extruded.

  Mixing of the polyester resin (1) and the polyester resin (2) may be performed before melt extrusion at the time of film production, or may be performed by melt extrusion after mixing both polyester resins in advance.

  Examples of the phosphorus compound contained in the polyester resin (2) include phosphoric acid compounds, phosphonic acid compounds, phosphinic acid compounds, phosphorous acid compounds, phosphonous acid compounds, and phosphinic acid compounds. .

  Examples of the phosphoric acid compound include phosphoric acid, dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diamyl phosphate, dihexyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, triamyl phosphate, triamyl phosphate Examples include hexyl phosphate and esters of phosphoric acid and alkylene glycol.

  Examples of phosphonic acid compounds include methylphosphonic acid, methylphosphonic acid dimethyl, methylphosphonic acid diphenyl, phenylphosphonic acid, phenylphosphonic acid dimethyl, phenylphosphonic acid diphenyl, benzylphosphonic acid dimethyl, benzylphosphonic acid diethyl, triethylphosphonoacetate, tributyl. Examples thereof include phosphonoacetate, tri (hydroxyethyl) phosphonoacetate, tri (hydroxypropyl) phosphonoacetate, and tri (hydroxybutyl) phosphonoacetate.

  Examples of the phosphinic acid compound include diphenylphosphinic acid, methyl diphenylphosphinate, phenyl diphenylphosphinate, phenylphosphinic acid, methyl phenylphosphinate, phenylphenylphosphinate, 2-carboxyethyl-methylphosphinic acid, 2-carboxyethyl. -Ethylphosphinic acid, 2-carboxyethyl-propylphosphinic acid, 2-carboxyethyl-phenylphosphinic acid, 2-carboxyethyl-m-toluylphosphinic acid, 2-carboxyethyl-p-toluylphosphinic acid, 2-carboxyethyl- Xylylphosphinic acid, 2-carboxyethyl-benzylphosphinic acid, 2-carboxyethyl-m-ethylbenzylphosphinic acid, 2-carboxymethyl-methylphosphinic acid, 2-carbo Cymethyl-ethylphosphinic acid, 2-carboxyethyl-propylphosphinic acid, 2-carboxymethyl-phenylphosphinic acid, 2-carboxymethyl-m-toluylphosphinic acid, 2-carboxymethyl-p-toluylphosphinic acid, 2-carboxymethyl -Xylylphosphinic acid, 2-carboxymethyl-benzylphosphinic acid, 2-carboxymethyl-m-ethylbenzylphosphinic acid, and cyclic anhydrides thereof, or methyl ester, ethyl ester, propyl ester, butyl ester, Examples thereof include ethylene glycol ester, propion glycol ester, and ester with butanediol.

  Phosphorous acid compounds include, for example, phosphorous acid and dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, diamyl phosphite, dihexyl phosphite, trimethyl phosphite, triethyl phosphite, triphenyl Phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylene diphosphite, phosphorous acid and alkylene glycol Examples include esters.

  Examples of the phosphonous acid compound include methylphosphonous acid, dimethyl methylphosphonite, diphenyl methylphosphonous acid, phenylphosphonous acid, dimethyl phenylphosphonous acid, and diphenyl phenylphosphonous acid.

  The phosphorous compound may be the same or different from that used for the polyester resin (1), but phosphoric acid or its derivative is preferably used.

  The polyester resin (2) is a thermoplastic polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, and is preferably a polyester containing aromatic dicarboxylic acid units of 70 mol% or more of the acid component. More preferably, it is a polyester containing 85 mol% or more of an aromatic dicarboxylic acid unit, and particularly preferably a polyester containing 95 mol% or more of an aromatic dicarboxylic acid unit of an acid component, Copolymerized or blended.

  Examples of the aromatic dicarboxylic acid component constituting the polyester resin (2) include aromatic dicarboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl 4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. Examples thereof include functional derivatives thereof.

  Examples of the glycol component constituting the polyester resin (2) include aliphatic glycols such as ethylene glycol, 1,3-trimethylene glycol, and tetramethylene glycol, and alicyclic glycols such as cyclohexanedimethanol. .

  The polyester resin (2) is preferably a polyester whose main structural unit is composed of ethylene terephthalate, more preferably 70 mol% or more of ethylene terephthalate units, and isophthalic acid, neopentyl glycol, 1, It is a copolyester containing 4-cyclohexanedimethanol and the like, particularly preferably a polyester containing 90 mol% or more of ethylene terephthalate units.

  When the polyester resin (2) is a copolymer, at least one of a dicarboxylic acid component or a glycol component is used in combination with at least one of the dicarboxylic acid component and the glycol component when the raw material is charged. Hereinafter, a copolymer polyester in which a copolymer component is introduced into the main chain of ethylene terephthalate in polyethylene terephthalate starting from terephthalic acid and ethylene glycol will be described as a representative example of the polyester resin (2).

  When dicarboxylic acid is used as a copolymerization component, isophthalic acid, diphenyl 4,4′-dicarboxylic acid, diphenoxyethane dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl ketone are used as the dicarboxylic acid. Aromatic dicarboxylic acids such as dicarboxylic acids and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, fats such as adipic acid, sebacic acid, succinic acid, glutaric acid and dimer acid Aromatic dicarboxylic acids and functional derivatives thereof, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid, and functional derivatives thereof can be used.

  When glycol is used as a copolymerization component, diethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, 2-ethyl-2- Aliphatic glycols such as butyl-1,3-propanediol, neopentyl glycol, dimer glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol 2,5-norbornane dimethylol and other alicyclic glycols, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, bis It is possible to use aromatic glycols such as 4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, alkylene oxide adducts of bisphenol A, polyalkylene glycols such as polyethylene glycol, polybutylene glycol, and the like. it can.

  Furthermore, when using a polyfunctional compound as another copolymerization component, trimellitic acid, pyromellitic acid, or the like can be used as the acid component, and glycerin or pentaerythritol can be used as the glycol component. However, the blending amount of these polyfunctional compounds must be such that the polyester is substantially linear. Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

  The polyester resin (2) is a method of copolymerizing by adding the phosphorus compound at the time of polycondensation, or kneading at least one selected from a general-purpose polyester resin and the phosphorus compound with an extruder, for example, a twin screw extruder. However, it is not limited to these.

  In the case of the method of copolymerization by adding the above phosphorus compound at the time of polycondensation of the polyester resin (2), for example, a polyester obtained by adding a phosphorus compound at the time of polycondensation of terephthalic acid and ethylene glycol for copolymerization is a representative example. The production method will be described below.

  In any method employed for the polycondensation of an esterification reaction product or a transesterification product of terephthalic acid or an ester-forming derivative thereof (for example, dimethyl terephthalate) with ethylene glycol into a polyester. Can be synthesized. The phosphorus compound is added during the production of the polyester, and the addition time can be added at any stage from the initial stage of the esterification process to the late stage of the initial condensation. It is preferable to add it after the completion of the conversion step and later in the initial condensation. In the case of the transesterification method, it can be added before the transesterification reaction, in the transesterification reaction process, or at any stage from the end of the transesterification reaction to the late stage of the initial condensation.

For example, in the case of the direct esterification method, the following production conditions are preferable.
The esterification reaction is carried out at 230 to 250 ° C. under normal pressure to increased pressure for 0.5 to 5 hours so that the esterification reaction rate is at least 95%, preferably 98% or more. Next, the first stage polycondensation is carried out at 240 to 255 ° C., preferably 240 to 250 ° C., more preferably 240 to 248 ° C., and 300 to 0.1 Torr for 0.5 to 2 hours. Further, the polycondensation is carried out at 250 to 290 ° C., preferably 250 to 280 ° C., more preferably 250 to 275 ° C., and 10 to 0.1 Torr, preferably 5 to 0.1 Torr to the desired degree of polymerization. The phosphorus compound is added at any stage from the end of esterification to the end of the first stage polycondensation. It is also important to carry out the first stage polycondensation reaction at 250 ° C. or lower.

  Examples of the starting material terephthalic acid or ethylene glycol include virgin terephthalic acid derived from para-xylene or ethylene glycol derived from ethylene, as well as methanol decomposition and ethylene glycol decomposition from used PET bottles. A recovered raw material such as terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered by the chemical recycling method can also be used as at least a part of the starting raw material. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

  Examples of the polycondensation catalyst used for producing the polyester resin (2) include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, indium, thallium, germanium, tin, lead, bismuth, and scandium. , Yttrium, Niobium, Zirconium, Hafnium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Ruthenium, Rhodium, Palladium, Tellurium, Tantalum, Tungsten, Gallium, Aluminum, Antimony, Germanium, Titanium, Silicon, Silver One or more metal compounds selected from the group consisting of, etc. are used, and in particular, antimony compounds, germanium compounds, and tungsten compounds are most suitable because the catalytic action is not easily deactivated by the phosphorus compounds. That. In addition, you may use the same thing as the polycondensation catalyst used when manufacturing the said polyester resin (1).

  Specific examples of the antimony compound include antimony trioxide, antimony acetate, antimony tartrate, antimony tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony.

  Specific examples of the germanium compound include amorphous germanium dioxide, crystalline germanium dioxide, germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, germanium phosphite. And the like.

  Tungsten compounds include compounds such as tungstic acid, lithium tungstate, potassium tungstate, sodium tungstate, calcium tungstate, barium tungstate, cobalt tungstate, copper tungstate, manganese tungstate, tungsten ethoxide, ammonium tungstate, etc. Is mentioned.

Further, in the production of the polyester resin (2), a basic nitrogen compound can be used in order to suppress the production of diethylene glycol. As the basic nitrogen compound, any of aliphatic, alicyclic, aromatic and heterocyclic nitrogen compounds may be used.
Examples include triethylamine, tributylamine, dimethylaniline, dimethylaniline, pyridine, quinoline, dimethylbenzylamine, piperidine, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, imidazole, and imidazoline. These compounds may be used in free form or as a salt of lower fatty acid or TPA.

  The addition of these basic nitrogen compounds to the reaction system can be appropriately selected at any stage until the initial polycondensation reaction is completed, and may be used alone or in combination of two or more. Also good. The blending amount of these basic nitrogen compounds is preferably 0.01 to 1 mol%, more preferably 0.05 to 0.7 mol%, particularly preferably 0.1 to 0. 5 mol%.

  Further, when the production of the polyester resin (2) is performed by a method of blending a phosphorus compound with a general-purpose polyester resin, a method of melt-kneading the dried polyester resin and the phosphorus compound with a twin screw extruder into a chip, A method in which the polyester resin granules are immersed in an aqueous solution of a phosphorus compound or an organic solvent, or a method in which these solutions are attached to the surface is suitable.

  The intrinsic viscosity of the polyester resin (2) is preferably 0.45 to 1.00 dl / g, more preferably 0.48 to 0.90 dl / g, and particularly preferably 0.50 to 0.85 dl. / G, most preferably 0.55 to 0.80 dl / g. The polyester resin (2) having an intrinsic viscosity of 0.60 dl / g or more is preferably produced by a method in which a polymer obtained by melt polycondensation is polymerized in a solid state.

  When the intrinsic viscosity is less than 0.45 dl / g, there are problems such that breakage frequently occurs during film production, transparency of the obtained film is lowered, and mechanical strength is lowered. In addition, in order to produce a polyester resin having an intrinsic viscosity exceeding 1.00 dl / g, the polycondensation time is very long, resulting in an increase in cost. When a film is produced by kneading 2) with another polyester resin, the kneading is incomplete and it becomes difficult to obtain a film of uniform quality.

  In addition, the polyester resin (2) has a known ultraviolet absorber, antioxidant, oxygen scavenger, externally added particles, and internal components during the polymerization reaction to such an extent that the physical properties such as polymer color and hydrolyzability are not impaired. It is also possible to use various additives such as internally precipitated particles, release agents, nucleating agents, stabilizers, antistatic agents, bluing agents, dyes, pigments, and the like.

  The polyester resin (1) and the polyester resin (2) may have the same or different polyester skeleton.

  Furthermore, the activity of the polycondensation catalyst of the polyester resin (1) may be deactivated by directly mixing the phosphorus compound with the polyester resin (1). When using the deactivation method of the catalytic activity of the polyester with the phosphorus compound, the phosphorus compound may be mixed with the polyester resin (1) before the melt extrusion step during film production, or the polyester resin (1) in advance. A polyester resin obtained by mixing and phosphorus extrusion with a phosphorus compound may be used as a film raw material. That is, you may implement by any method of the method of mixing a phosphorus compound with a polyester resin (1), melt-extruding, or the method of adding a phosphorus compound to a molten polyester resin (1). Moreover, you may use together the method of mixing said polyester resin (1) and polyester resin (2), and the method of mixing a phosphorus compound directly to polyester resin (1).

In the method of deactivating the polycondensation catalyst by the phosphorus compound, for example, Al atoms and P atoms of a polyester film obtained by forming a film using a polyester obtained by an aluminum-based polycondensation catalyst system remain. The blending ratio of the polyester resin (1) to the polyester resin (2) and the phosphorus compound is adjusted so that the molar ratio (P / Al) and the residual amount of P atoms are the amounts represented by the following formulas (1) and (2). It is preferable to adjust.
2.5 ≦ P / Al (molar ratio) ≦ 20 (1)
20 ≦ P (ppm) ≦ 200 (2)

  If both formulas are smaller than the lower limit value, the deactivation effect of the polycondensation catalyst is insufficient, and the effect of suppressing the formation of the cyclic trimer in the molten state of the polyester resin in the film forming process is small. On the other hand, when the upper limit is exceeded, the deactivation effect of the polycondensation catalyst is saturated and the intrinsic viscosity of the polyester resin is lowered.

  As described above, by using the molding polyester film of the present invention, it is difficult to mold with the conventional biaxially oriented polyester film, and the vacuum at a molding pressure of 10 atm or less is low. Also in molding methods such as molding and pressure molding, it is possible to obtain a molded product with good finish. In addition, these molding methods are advantageous in terms of economy in the production of molded products because the molding costs are low. Therefore, application to these molding methods can most effectively exert the effect of the molding polyester film of the present invention.

  On the other hand, although the mold and the molding apparatus are expensive and disadvantageous in terms of economy, mold molding is characterized in that a molded product having a more complicated shape than that of the molding method is molded with high accuracy. Therefore, when the mold is molded using the molding polyester film of the present invention, molding is possible at a lower molding temperature and the finished quality of the molded product is improved as compared with the conventional biaxially oriented polyester film. The remarkable effect is expressed.

  Furthermore, the molded product thus molded has excellent elasticity and shape stability (heat shrinkage characteristics, thickness unevenness) when used in a room temperature atmosphere, and also has excellent solvent resistance and heat resistance, as well as environmental impact. Therefore, it is preferably used as a molded member for various portable equipment casings, nameplates for home appliances, nameplates for automobiles, dummy cans, building materials, decorative plates, decorative steel plates, transfer sheets, and the like.

  The molding polyester film of the present invention is also suitable as a molding material that is molded using a molding method such as press molding, laminate molding, in-mold molding, draw molding, or bending molding, in addition to the above-described molding methods. is there.

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

(1) Intrinsic viscosity 0.1 g of a chip sample was precisely weighed, dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 60/40 (mass ratio), and measured at 30 ° C. using an Ostwald viscometer. In addition, the measurement was performed 3 times and the average value was calculated | required.

(2) Content of cyclic trimer in polyester resin 300 mg of a sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixture (= 2/3; volume ratio), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, brought to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

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

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

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

(6) Increase in haze after heat-treating the film at 170 ° C. for 10 minutes (ΔH)
Under no load, the haze of the film before and after being heat-treated for 10 minutes in a gear oven at 170 ° C. was measured, and the difference between the haze after the heat treatment and the haze before the heat treatment was defined as ΔH. In addition, the measurement of haze was based on JIS-K7136, and was measured using the haze meter (The Nippon Denshoku Industries Co., Ltd. make, 300A). In addition, the measurement was performed twice and the average value was calculated | required.

(7) Amount of cyclic trimer on the film surface An A4 size film is brought into contact with chloroform for 5 minutes to dissolve the oligomer deposited on the surface. About the obtained chloroform solution, the cyclic trimer was quantified by the high performance liquid chromatography method. The amount of the cyclic trimer on the film surface (mg / m ² ) was determined by dividing the amount of the cyclic trimer by the surface area of the film.

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

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

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

(9) Surface roughness (Ra)
Based on JIS-B601-2001, Ra was measured with Surfcom 304B (manufactured by Tokyo Seimitsu Co., Ltd.). The measurement conditions were a cutoff of 0.08 μm, a stylus radius of 2 μm, a measurement length of 0.8 mm, and a measurement speed of 0.03 mm / second.

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

(11) Degree of plane orientation (ΔP)
Using a sodium D line (wavelength 589 nm) as a light source and using an Abbe refractometer, the refractive index (Nz) in the longitudinal direction of the film, the refractive index (Ny) in the width direction, and the refractive index (Nz) in the thickness direction are measured. The degree of plane orientation (ΔP) was calculated from the equation.
ΔP = ((Nx + Ny) / 2) −Nz

(12) Unwindability of roll-shaped film The formed film is wound around a 3-inch paper tube having a width of 300 mm and a length of 200 m, and is left for 72 hours in an atmosphere of 23 ° C. and 65 RH%. Then, when the film was installed in the vacuum evaporation machine and unwound at a speed of 50 m / min in an atmosphere of 1 × 10 ⁻⁴ torr, the following evaluation was made until the winding was completed. Judgment criteria were ◯ when there was no problem from all viewpoints, and x when there was at least one problem.
a. Film tear b. Occurrence of flapping c. Generation of loud sounds due to friction between films or between film / roll

(13) Glass transition temperature (Tg) and melting point (Tm) of the raw material
Using a differential scanning calorimeter (Mac Science, DSC3100S), about 7 mg of the raw material extruded under the conditions of each example was placed in a sample pan, the pan was capped, and the temperature was increased from room temperature to 300 ° C. in a nitrogen gas atmosphere. The temperature was measured at a temperature increase rate of 20 ° C./min. Tg (° C.) was determined based on JIS-K7121-1987, 9.3, and the melting point was determined by the melting peak temperature (Tpm) defined in 9.1.

(14) Formability (a) Vacuum formability After 5 mm square printing is performed on the film, the film is heated with an infrared heater heated to 500 ° C. for 10 to 15 seconds, and then at a mold temperature of 30 to 100 ° C. Vacuum forming was performed. In addition, the heating conditions selected the optimal conditions within the said range with respect to each film. The shape of the mold was a cup shape, the opening had a diameter of 50 mm, the bottom part had a diameter of 40 mm, the depth was 50 mm, and all corners were curved with a diameter of 0.5 mm. .

Five molded products that were vacuum-molded under the optimum conditions were evaluated for moldability and finish, and ranked according to the following criteria. In addition, (double-circle) and (circle) were set as the pass, and x was set as the disqualification.
A: (i) The molded product is not torn,
(Ii) The corner radius of curvature is 1 mm or less, and the printing deviation is 0.1 mm or less,
(Iii) Further, there is no appearance defect corresponding to ×: (i) The molded product is not torn,
(Ii) The radius of curvature of the corner is more than 1 mm and not more than 1.5 mm, or the printing deviation is 0.
More than 1mm and less than 0.2mm,
(Iii) Furthermore, there is no appearance defect corresponding to ×, and there is no problem in practical use. ×: The molded product is broken, or even if there is no breakage, it falls under any of the following items (i) to (iv) Things to do (i) Corner radius of curvature exceeds 1.5 mm (ii) Appearance is bad with large wrinkles
(Iii) The film is whitened and the transparency is lowered
(Iv) Print misalignment exceeding 0.2 mm

(B) Compressive air moldability After 5 mm square printing is performed on the film, the film is heated for 10 to 15 seconds with an infrared heater heated to 500 ° C., and then subjected to 4 atm at a mold temperature of 30 to 100 ° C. Crushing was performed under pressure. In addition, the heating conditions selected the optimal conditions within the said range with respect to each film. The shape of the mold is a cup shape, the opening has a diameter of 60 mm, the bottom has a diameter of 55 mm, a depth of 50 mm, and all corners are curved with a diameter of 0.5 mm. .

The moldability and finish of five molded products that were pressure-molded under optimal conditions were evaluated and ranked according to the following criteria. In addition, (double-circle) and (circle) were set as the pass, and x was set as the disqualification.
A: (i) There is no tear in the molded product,
(Ii) The corner radius of curvature is 1 mm or less, and the printing deviation is 0.1 mm or less,
(Iii) Further, there is no appearance defect corresponding to ×: (i) The molded product is not torn,
(Ii) The radius of curvature of the corner is more than 1 mm and not more than 1.5 mm, or the printing deviation is 0.
More than 1mm and less than 0.2mm,
(Iii) Furthermore, there is no appearance defect corresponding to ×, and there is no problem in practical use. ×: The molded product is broken, or even if there is no breakage, it falls under any of the following items (i) to (iv) What to do (i) The corner radius of curvature exceeds 1.5 mm (ii) The appearance with large wrinkles and the appearance is bad (iii) The film is whitened and the transparency is lowered (iv) The printing deviation is 0.2 mm More than

(C) Mold formability After printing on the film, contact heating with a hot plate heated to 100 to 140 ° C for 4 seconds, followed by press molding at a mold temperature of 30 to 70 ° C and a holding time of 5 seconds. It was. In addition, the heating conditions selected the optimal conditions within the said range with respect to each film. The shape of the mold is a cup shape, the opening has a diameter of 50 mm, the bottom has a diameter of 40 mm, a depth of 30 mm, and all corners are curved with a diameter of 0.5 mm. .

The moldability and finish of the five molded products molded under optimal conditions were evaluated and ranked according to the following criteria. In addition, (double-circle) and (circle) were set as the pass, and x was set as the disqualification.
A: (i) There is no tear in the molded product,
(Ii) The corner radius of curvature is 1 mm or less, and the printing deviation is 0.1 mm or less,
(Iii) Further, there is no appearance defect corresponding to ×: (i) The molded product is not torn,
(Ii) The radius of curvature of the corner is more than 1 mm and not more than 1.5 mm, or the printing deviation is 0.
More than 1mm and less than 0.2mm,
(Iii) Furthermore, there is no appearance defect corresponding to ×, and there is no problem in practical use. ×: The molded product is broken, or even if there is no breakage, it falls under any of the following items (i) to (iv) What to do (i) Where the corner radius of curvature exceeds 1.5 mm (ii) Where the appearance is bad with large wrinkles (iii) When the film is whitened and its transparency is reduced (iv) Print deviation is 0.2 mm More than

(15) Solvent resistance The sample was immersed in toluene adjusted to 25 ° C. for 30 minutes, and the appearance change before and after the immersion was determined according to the following criteria, and “◯” was accepted. The haze value was measured by the method described above.
○: Little change in appearance, change in haze value is less than 1% ×: Change in appearance is observed, or change in haze value is 1% or more

(16) Print quality The film before printing was heat-treated at 90 ° C. for 30 minutes, and then four-color screen printing was performed.
Furthermore, the film provided with the printing layer was dried at 80 ° C. for 30 minutes. Evaluation of printing quality was made by visually judging the printing appearance such as the following clear feeling, printing suitability, printing misalignment and the like through the film from the back side, not from the printing side. As the judgment criteria, “O” indicates that there is no problem from all viewpoints, and “X” indicates that there is a problem in at least one point.
a. Clear feeling: The printed pattern is blocked by the base film or coating layer.
It should look clear without any problems.
b. Printability: Color unevenness and missing due to poor transfer of printing ink
Do not follow c. Printing misalignment: The misalignment of printing cannot be determined visually.

Example 1
(Preparation of polyester film)
The following three types of polyester resins A1, B1, and B5 were prepared as film materials.
The first polyester resin (A1) has an intrinsic viscosity of 0 as an aromatic dicarboxylic acid component and a terephthalic acid unit of 100 mol%, a diol component of an ethylene glycol unit of 40 mol% and a neopentyl glycol unit of 60 mol%. .69 dl / g copolymerized polyester.

  The second polyester resin (B1) is polyethylene terephthalate containing 0.04% by mass of amorphous silica having an intrinsic viscosity of 0.69 dl / g and an average particle diameter (SEM method) of 1.5 μm.

  The above chip (A1) and chip (B1) were produced using an aluminum-based catalyst, and the polyester resin was dried at 160 ° C. under reduced pressure. Then, nitrogen gas containing 400 ppm of ethylene glycol was added to 1 kg of crude polyester. The reaction system was adjusted to a slight pressure of 1.2 kg / cm 2 and heated at 215 ° C. for 20 hours to reduce the oligomer (low OLG). The intrinsic viscosity of the obtained polyester was almost the same as that before the treatment, and the content of the cyclic trimer of the chip (A1) was 2500 ppm, and the content of the cyclic trimer of the chip (B1) was 3900 ppm.

  The third polyester resin (B5) is a catalyst-reused polyethylene terephthalate having an intrinsic viscosity of 0.61 dl / g and containing 2000 ppm of phosphorus compounds in terms of phosphorus atoms. In addition, catalyst deutilization polyester (B5) was obtained by the following method.

(Manufacture of polyester resin (B5) that lost catalyst)
A batch polymerization can is charged with high-purity terephthalic acid and twice its molar amount of ethylene glycol, 0.3 mol% of triethylamine is added to the acid component, and water is removed from the system at 245 ° C under a pressure of 0.25 MPa. The esterification reaction was carried out for 120 minutes while distilling off to obtain a mixture of bis (2-hydroxyethyl) terephthalate and oligomer (hereinafter referred to as BHET mixture) having an esterification rate of 95%. In this BHET mixture, a germanium dioxide / ethylene glycol slurry and an ester of ethylene glycol and phosphoric acid (mono-, di-, tri-, ester mixture) / ethylene glycol solution were used as polycondensation catalysts. It added so that it might be set to 50 ppm in terms of atoms and 2000 ppm in terms of P atoms, and polycondensation was carried out according to a conventional method to obtain a catalyst deutilizing polyester resin having an IV of 0.61 dl / g. The obtained polyester resin was dried at 160 ° C. under reduced pressure, and then nitrogen gas containing 400 ppm of ethylene glycol was circulated at 40 liters per hour per 1 kg of the crude polyester, and this reaction system was fined at 1.2 kg / cm 2. The pressure was adjusted, heat treatment was performed at 215 ° C. for 20 hours, and a low oligomer (low OLG) treatment was performed, and the cyclic trimer content was reduced to 3200 ppm.

  After drying the copolymer polyester (A1) chip, the particle-containing polyethylene terephthalate (B1) chip, and the catalyst depleted polyester resin (B5) chip containing 2000 ppm in terms of P atoms, A1 / B1 It mixed so that it might become mass ratio of / B5 = 25/70/5. Subsequently, these chip mixtures were melt-extruded from the slit of the T die at 270 ° C. with an extruder, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, the amorphous mixture was adhered to the chill roll using an electrostatic application method. A stretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.3 times at 90 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film was guided to a tenter, preheated at 120 ° C. for 10 seconds, and the first half of the transverse stretching was stretched 3.9 times at 110 ° C. and the latter half at 100 ° C. Furthermore, the first heat treatment (TS1) was 205 ° C., and the second heat treatment (TS2) was heat-set at 235 ° C. while performing a 7% relaxation treatment in the transverse direction, and a biaxially stretched polyester having a thickness of 100 μm. A film was obtained.

  In the heat setting zone, an intermediate section of 2 m is provided between the stretching section, a far infrared heater is installed in the heating section of the heat setting zone, and the limit position where the shielding plate in each section does not contact the film Expanded and installed. Also in the cooling section after heating, section shielding is strengthened, an external return method is used as a clip return method, a clip cooling device is installed, and forced cooling is performed with cold air of 20 ° C., and the clip temperature at the tenter outlet is set to 40. Measures were taken to prevent clip fusion to below ℃.

Comparative Example 1
In the production of the copolymerized polyester (A1) and the particle-containing PET (B1) of Example 1, the copolymerized polyester (A2) and the polyester (A2) were prepared in the same manner as in Example 1 except that the low oligomer (OLG) treatment was not performed. Particle-containing PET (B2) was obtained. In Example 1, in the same manner as in Example 1 except that the copolymer polyester (A2) chip and the particle-containing PET (B2) chip were mixed so that the mass ratio was A2 / B2 = 25/75. A biaxially stretched polyester film was obtained. The copolymerized polyester (A2) obtained in this comparative example contained 7000 ppm, and the particle-containing PET (B2) contained 9500 ppm of cyclic trimer.

Comparative Example 2
In Comparative Example 1, a biaxially stretched polyester film was obtained in the same manner as in Comparative Example 1, except that the heat setting temperature was changed to 235 ° C. for both TS1 and TS2.

Comparative Example 3
In Comparative Example 1, a biaxially stretched polyester film was obtained in the same manner as in Comparative Example 1, except that the heat setting temperature was changed to 205 ° C. for both TS1 and TS2.

Example 2
(Coating solution adjustment)
A water-soluble urethane resin (1st solid copolymer 3.15% by mass of copolymer polyester resin (Toyobo Co., Ltd., Vylonal MD-1250) and a terminal isocyanate group blocked with a hydrophilic group in a 40% by mass aqueous solution of isopropanol (first Elastolone H-3) manufactured by Kogyo Seiyaku Co., Ltd. is a silica having a solid content of 5.85% by mass and an average particle size of 1.0 μm silica particles of 0.8% by mass and an average particle size of 0.05 μm based on the total resin The coating solution was adjusted so that the particles contained 10% by mass with respect to the total resin. The obtained coating solution was adjusted to pH 6.5 using a 5% by mass aqueous sodium bicarbonate solution. Subsequently, it filtered with the bag type filter (Sumitomo 3M Co., Ltd. product, liquid filter bag), and stirred at 15 degreeC in the coating liquid circulation system stock tank for 2 hours.

(Manufacture of laminated film)
In Example 1, instead of the polyethylene terephthalate chip (B1), the polyethylene terephthalate chip (B4) having a cyclic trimer content of 3900 ppm and substantially no particles and an intrinsic viscosity of 0.69 dl / g ) Was used in the same manner as in Example 1 to obtain an amorphous unstretched sheet. The discharge amount of the molten resin was adjusted so that the final film thickness was 188 μm.

  The obtained unstretched sheet was stretched 3.3 times at 90 ° C. in the longitudinal direction between the heating roll and the cooling roll. Subsequently, the said coating liquid was apply | coated to the single side | surface of a uniaxially stretched film so that the thickness of the resin solid content before extending | stretching might be set to 0.9 micrometer by the reverse kiss coating method. The laminated film having the coating layer was guided to a tenter while being dried, preheated at 120 ° C. for 10 seconds, and the first half of transverse stretching was stretched 3.9 times at 110 ° C. and the latter half at 100 ° C. Further, the first heat treatment (TS1) is 205 ° C., the second heat treatment (TS2) is heat-set at 235 ° C. while performing a 7% relaxation treatment in the lateral direction, and has a coating layer on one side. A biaxially stretched polyester film having a thickness of 188 μm was obtained.

  In the heat setting zone, an intermediate section of 2 m is provided between the stretching section, a far infrared heater is installed in the heating section of the heat setting zone, and the limit position where the shielding plate in each section does not contact the film Expanded and installed. Also in the cooling section after heating, section shielding is strengthened, an external return method is used as a clip return method, a clip cooling device is installed, and forced cooling is performed with cold air of 20 ° C., and the clip temperature at the tenter outlet is set to 40. Measures were taken to prevent clip fusion to below ℃.

Example 3
In addition to the chip (B5) used in Example 1, the following chips (A3), (B6), and (C) were prepared as film materials.

  The chip (A3) was prepared according to the method of Example 1, and the resin component was 100 mol% terephthalic acid unit as the aromatic dicarboxylic acid component, 70 mol% ethylene glycol unit and 30 mol% neopentylglycol unit as the diol component. Is a copolyester chip having an intrinsic viscosity of 0.77 dl / g. The content of the cyclic trimer in the chip (A3) was 3200 ppm.

  The chip (B6) is a polyethylene terephthalate chip prepared according to the method of Example 1 and having an intrinsic viscosity of 0.77 dl / g. The content of the cyclic trimer in the chip (B6) was 3900 ppm.

  Chip (C) is a trimethylene terephthalate (PTT) chip having an intrinsic viscosity of 0.75 dl / g. In addition, a cyclic trimer was not detected.

After the chips are dried, chip (A3), chip (B6), chip (B
1) and chip (C) were mixed so as to have a mass ratio of 50/5/5/40. Subsequently, these chip mixtures were melt-extruded from the slit of the T die at 270 ° C. with an extruder, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, the amorphous mixture was adhered to the chill roll using an electrostatic application method. A stretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.5 times at 83 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the coating solution was applied to the chill roll surface side (F surface) of the uniaxially stretched film by a reverse kiss coating method so that the thickness of the resin solid before stretching was 0.9 μm. The laminated film having the coating layer was guided to a tenter while being dried, preheated at 95 ° C. for 10 seconds, and the first half of the transverse stretching was stretched 3.9 times at 80 ° C. and the latter half at 75 ° C. Furthermore, heat treatment was performed at 210 ° C. while the first heat treatment (TS1) was 190 ° C. and the second heat treatment (TS2) was subjected to a relaxation treatment of 7% in the transverse direction, and a biaxially stretched polyester having a thickness of 50 μm. A film was obtained.

  In the heat setting zone, an intermediate section of 2 m is provided between the stretching section, a far infrared heater is installed in the heating section of the heat setting zone, and the limit position where the shielding plate in each section does not contact the film Expanded and installed. Also in the cooling section after heating, section shielding is strengthened, an external return method is used as a clip return method, a clip cooling device is installed, and forced cooling is performed with cold air of 20 ° C., and the clip temperature at the tenter outlet is set to 40. Measures were taken to prevent clip fusion to below ℃.

Comparative Example 4
In Example 3, a biaxially stretched polyester film was obtained in the same manner as in Example 3 except that the heat setting temperature was changed to 205 ° C. for both TS1 and TS2.

Comparative Example 5
In Example 3, a biaxially stretched polyester film was obtained in the same manner as in Example 2 except that the heat setting temperature was changed to 180 ° C. (TS1) and 220 ° C. (TS2).

Example 4
The raw material composition of Example 4 is used as a core layer, and a chip in which chips (A3), chips (B6), and chips (B5) are mixed at a mass ratio of 50/45/5 is fed into another extruder as a raw material for the skin layer. And melted at 280 ° C., joined with a feed block so that the thickness ratio of the raw material of the core layer and the skin layer / core layer / skin layer = 10/80/10 was extruded from a T-die at 270 ° C. Except for the above, a biaxially stretched polyester film was obtained under the conditions shown in Table 4.
The melting point value of the original fabric in Table 4 is the value of the core layer, and the melting point of the skin layer was 243 ° C.

Example 5
As raw materials for Example 5, the following chip (D) and chip (E) were prepared in addition to the chip (B6) and chip (B5).

  Chip (D) has an intrinsic viscosity of 0.71 dl / g, comprising 60 mol% of terephthalic acid units and 40 mol% of isophthalic acid units as aromatic dicarboxylic acid components and 100 mol% of ethylene glycol units as diol components. This is a copolyester chip. The content of the cyclic trimer in the chip (D) was 3000 ppm.

  The chip (E) has an intrinsic viscosity of 0.71 dl / unit, comprising 60 mol% of terephthalic acid units and 40 mol% of naphthalenedicarboxylic acid components as aromatic dicarboxylic acid components and 100 mol% of ethylene glycol units as diol components. g copolymerized polyester chip. The content of the cyclic trimer in the chip (E) was 3000 ppm.

  Chip (B6), chip (B5) and the above-mentioned copolymer polyester chip (D) and polyethylene terephthalate chip (E) were mixed at a mass ratio of 45: 5: 25: 25 and dried. . Subsequently, these chip mixtures were melt-extruded from the slit of the T die at 270 ° C. with an extruder, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, the amorphous mixture was adhered to the chill roll using an electrostatic application method. A stretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.3 times at 90 ° C. in the longitudinal direction between the heating roll and the cooling roll. Subsequently, the said coating liquid was apply | coated to the single side | surface of a uniaxially stretched film so that the thickness of the resin solid content before extending | stretching might be set to 0.9 micrometer by the reverse kiss coating method. The laminated film having the coating layer was dried and guided to a tenter, preheated at 120 ° C. for 10 seconds, and the first half of transverse stretching was stretched 3.9 times at 110 ° C. and the latter half at 100 ° C. Further, the first heat treatment (TS1) is 205 ° C., the second heat treatment (TS2) is heat-set at 238 ° C. while performing a 7% relaxation treatment in the lateral direction, and has a coating layer on one side. A biaxially stretched polyester film having a thickness of 100 μm was obtained.

  In the heat setting zone, an intermediate section of 2 m is provided between the stretching section, a far infrared heater is installed in the heating section of the heat setting zone, and the limit position where the shielding plate in each section does not contact the film Expanded and installed. Also in the cooling section after heating, section shielding is strengthened, an external return method is used as a clip return method, a clip cooling device is installed, and forced cooling is performed with cold air of 20 ° C., and the clip temperature at the tenter outlet is set to 40. Measures were taken to prevent clip fusion to below ℃.

Comparative Example 6
The comparative example 6 is an experiment in which Example 1 of Japanese Patent Application Laid-Open No. 2001-347565 was re-examined and compared with the prior art.
Wet dimethyl terephthalate and ethylene glycol, magnesium acetate (M) and antimony trioxide as catalyst, phosphoric acid (P) as additive, wet method silica with an average particle size (SEM method) of 1.5 μm (0.08% by mass) ) Was added, and polyethylene terephthalate was polymerized by a conventional method to obtain a polyethylene terephthalate (PET) chip (B7). The obtained PET chip (B7) had an intrinsic viscosity of 0.65 dl / g, a carboxyl end group concentration of 25 eq / ton, and an M / P molar ratio of 2.5.

  The PET chip (B7) was vacuum-dried at 180 ° C. for 4 hours, then supplied to a melt extruder, extruded into a sheet form from a slit-shaped die, and adhered to a mirror surface cooling drum by electrostatic application (3.0 kV). An unstretched sheet was prepared by cooling and solidification. The unstretched sheet was first stretched 3.0 times in the longitudinal direction with a roll heated to a temperature of 105 ° C., further stretched 3.2 times in the width direction at a stretching temperature of 125 ° C., and then at 195 ° C. A biaxially stretched polyester film having a thickness of 100 μm and a degree of plane orientation of 0.138 was obtained by performing 6% relaxation in the direction and heat treatment for 6 seconds.

  Regarding Examples 1 to 5 and Comparative Examples 1 to 6, the raw material composition and polymer characteristics of the polymers used are shown in Table 1, and the production conditions and characteristics of the films are shown in Tables 2 to 5.

  Even if the biaxially oriented polyester films obtained in Examples 1 to 5 were molded by a vacuum molding method or a pressure molding method having a low molding pressure at the time of molding, molded products having good finish were obtained. Moreover, the solvent resistance and dimensional stability of the obtained molded product were also good. Further, the amount of the cyclic trimer on the film surface was small, and the increase in the amount of the cyclic trimer on the film surface when heat-treated was small. Accordingly, there was little mold contamination during molding. The film obtained in Example 2 was excellent in printing quality because it was superior in transparency as compared with the film obtained in Example 1 containing silica particles in the base film.

  On the other hand, the films obtained in Comparative Examples 3 and 6 were inferior in moldability by the vacuum forming method or the pressure forming method, and the finished quality of the molded product was not good. The films obtained in Comparative Examples 1, 2, 3, and 6 have a large amount of cyclic trimer on the film surface and a large increase in the amount of cyclic trimer on the film surface when heated. As a result, the transparency of the film was lowered. There were also many mold stains. Furthermore, the films obtained in Comparative Examples 2, 4, and 5 were inferior in terms of film unwinding properties.

  The molding polyester film of the present invention is excellent in moldability at the time of heat molding at a low temperature and low pressure, and therefore can be applied to a wide variety of molding methods, and when used in a room temperature atmosphere as a molded product, It has the advantages of excellent shape stability (heat shrinkage characteristics, thickness unevenness), solvent resistance, heat resistance, and low environmental impact. Further, when unwinding a long film wound up in a roll shape at the time of post-processing, blocking and tearing are unlikely to occur, resulting in excellent productivity. In addition, since the content of the cyclic trimer is small, there is an advantage that problems such as generation of defects due to the cyclic trimer, mold contamination during molding, and a decrease in transparency are small. Furthermore, since it is highly excellent in smoothness and transparency, the printing quality improving layer of the film has various types such as letterpress printing, intaglio printing, planographic printing, screen printing, offset printing, gravure printing, inkjet printing, flexographic printing, etc. Designs such as printing layers, design layers, etc. are applied by decoration methods such as printing decoration, printing, transfer, painting, painting, vapor deposition, sputtering, CVD, laminating, etc., then mold molding, pressure molding, vacuum molding, etc. It is suitable for a three-dimensional decoration method that is molded by various molding methods, and has excellent in-mold moldability and emboss moldability. Therefore, it is suitable as a casing for various portable devices, a member for nameplates or a member for building materials of home appliances and automobiles, and greatly contributes to the industry.

Claims (6)

  A polyester film for molding made of a biaxially oriented polyester film containing a copolymerized polyester, (1) 100% elongation stress in the longitudinal direction and the width direction of the film is 40 to 300 MPa at 25 ° C. and 100 ° C. 1 to 100 MPa, (2) the thermal shrinkage in the longitudinal direction and the width direction at 150 ° C. of the film is 0.01 to 5.0%, (3) the haze is 0.1 to 3.0%, (4) at least The surface roughness (Ra) of a single-sided film is 0.005 to 0.030 μm, (5) the degree of plane orientation is 0.095 or less, and (6) no increase in haze after heat-treating the film at 170 ° C. for 10 minutes. A polyester film for molding, characterized by being 3% or less.   A copolymer polyester comprising (a) an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol; or (b) terephthalic acid and isophthalic acid The polyester film for molding according to claim 1, wherein the polyester film is a copolyester composed of an aromatic dicarboxylic acid component containing glycine and a glycol component containing ethylene glycol.   The polyester constituting the biaxially oriented polyester film further comprises a 1,3-propanediol unit or a 1,4-butanediol unit as a glycol component.   The polyester film for molding according to any one of claims 1 to 3, wherein the biaxially oriented polyester film has a melting point of 200 to 245 ° C.   A polyester film for molding, in which a biaxially oriented polyester film is used as a base film, and a surface layer having a thickness of 0.01 to 5 μm is laminated on one or both sides of the base film, and the base film is substantially The polyester film for molding according to any one of claims 1 to 4, wherein no particles are contained in the particles, and the particles are contained only in the surface layer.   6. The molding polyester film according to claim 5, wherein the surface layer is mainly composed of an adhesion modifying resin and particles.