KR101086093B1 - Laminated polyester film for forming and process for producing the same - Google Patents

Abstract

The present invention is a laminated polyester film for molding by laminating a polyester B layer on one side or both sides of an A layer, wherein both the A layer and the B layer are composed of copolyester or copolyester and homopolyester. , The melting point (TmA: ℃) and the melting point (TmB: ℃) of the B layer simultaneously satisfy the following formulas (1) and (2), and the laminated polyester film has an orientation structure in both the A layer and the B layer. The moldability, transparency, solvent resistance, form stability and impact resistance at low temperatures and pressures at which the heat shrinkage at 150 ° C. is 6.0% or less in both the longitudinal and width directions and the thickness variation in the width direction is 10% or less. It is an object of the present invention to provide an excellent laminated polyester film for molding.

Description

Laminated polyester film and forming method thereof

The present invention is excellent in formability, in particular in low temperature and low pressure, excellent in moldability, transparency, solvent resistance, shape stability (heat shrinkage characteristics, thickness nonuniformity), and excellent impact resistance for home appliances, mobile phones, automobiles The present invention relates to a laminated polyester film for molding suitable as a member for interior or exterior materials or a building material, and a method for producing the same.

Conventionally, as a sheet for shaping | molding, the polyvinyl chloride film has typically been used suitably from a viewpoint of workability. However, there are problems in terms of environmental aptitude, such as generation of toxic gases during film combustion and bleed out of the plasticizer.

On the other hand, as a material excellent in environmental aptitude, an unstretched sheet made of polyester, polycarbonate, or acrylic resin has been used in a wide range of fields. In particular, the unstretched sheet made of polyester resin is excellent in moldability and laminate aptitude. However, because it is an unstretched sheet, it is inferior in terms of heat resistance and solvent resistance.

In addition, the unstretched sheet has insufficient impact resistance and shape stability (heat shrinkage characteristics). For this reason, if (a) the speed at the time of printing or molding processing is increased to improve productivity, breakage or holes may occur at the time of processing, (b) printing misalignment may occur due to heating at the time of molding, or (c) When exposed to a place where the temperature is higher than room temperature, there is a problem such that distortion occurs in the molded article.

In addition, in the case of depositing a metal such as aluminum on the unstretched sheet, when the heat shrinkage characteristics are deteriorated, there are problems such as small wrinkles at the time of vapor deposition resulting in difficulty in winding or insufficient glossiness. In the case of performing vacuum deposition, the processing speed is further increased, so that the sheet may break at the time of vapor deposition if the impact resistance is not sufficient.

As a method of solving the said problem, the method of using the biaxially stretched polyethylene terephthalate film which controlled the stress at 100% elongation of a film to a specific range is disclosed (for example, refer patent document 1, 2). .

Patent Document 1: Japanese Patent Application Laid-Open No. 2-204020

Patent Document 2: Japanese Patent Application Laid-Open No. 2001-347565

However, in the invention described in Patent Literature 1, excellent molding is achieved by adjusting the compounding amount of aliphatic glycol using a copolyester containing aliphatic glycol and reducing the stress at 100% elongation under an atmosphere of 150 ° C. It is described that the castle, planarity and heat resistance are obtained. However, it was insufficient in terms of both formability and heat resistance. On the other hand, in the invention described in Patent Literature 2, there have been problems in lowering the molding temperature and finishing properties of the molded body.

The present inventors have a copolyester resin as a component, the stress at 100% elongation of the film (25 ℃, 100 ℃), the storage modulus (100 ℃, 180 ℃), the thermal strain under the micro tension in the longitudinal direction ( By using the biaxially oriented polyester film in which 175 degreeC) exists in a specific range, the method of improving said problem was proposed (for example, refer patent document 3).

Patent Document 3: Japanese Patent Application Laid-Open No. 2005-290354

The above problem is greatly improved by the above method, and in the mold forming method having a high molding pressure during molding, it is possible to industrially provide a film that satisfies the market demand. Moreover, the finishing property is improved also in the shaping | molding method with low shaping | molding pressure at the time of shaping | molding, such as the pressure forming method and the vacuum shaping | molding method which have strong market demand.

However, when the biaxially oriented polyester film for molding is produced continuously for a long time, the film is torn during post-processing to the film (printing, lamination of metal film or metal oxide film, etc.), during molding, or when the molded article is used. Or blocking was prone to occur. For this reason, it is desired to improve the impact resistance of a film and to further improve stability of productivity and quality.

In addition, inventions have been proposed in which a film is formed in a laminated structure, the functions are shared in each layer so as to have chemical resistance in the skin layer, and sufficient moldability in the core layer, and both the chemical resistance and the moldability are proposed (for example, For example, refer patent document 4).

Patent Document 4: Japanese Patent Application Laid-Open No. 2005-335276

However, in the present invention, since the heat treatment temperature is increased until the core layer becomes substantially non-oriented structure, (1) elongation at room temperature is extremely low, and (2) whitens at heat. Therefore, the use range of the processing temperature is narrow, and (3) there is a problem that the appearance quality, stability and reproducibility deteriorate because the thickness unevenness is bad.

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and is excellent in moldability, in particular, moldability, transparency, solvent resistance, and shape stability (heat shrinkage characteristics and thickness nonuniformity) at low temperature and low pressure, and also impact resistance. It is providing the excellent laminated polyester film for molding and its manufacturing method.

Means to solve the problem

The laminated polyester film for shaping | molding of this invention which can solve the said subject, and its manufacturing method have the following structures.

That is, the 1st invention in this invention is a biaxially oriented laminated polyester film formed by laminating | stacking a polyester B layer on the single side | surface or both surfaces of a polyester A layer,

A-layer and B-layer are both copolyester or copolyester and homopolyester, and melting | fusing point (TmA: degreeC) of layer A and melting | fusing point (TmB: degreeC) of layer B are following Formula (1) And (2) at the same time,

The laminated polyester film has an orientation structure in both the A layer and the B layer, the heat shrinkage at 150 ° C. is 6.0% or less in both the longitudinal direction and the width direction, and the thickness variation in the width direction is 10% or less. It is a polyester film.

2nd invention is a glycol component in which a copolyester contains (a) aromatic dicarboxylic acid component, ethylene glycol, and branched aliphatic glycol or alicyclic glycol. The laminated polyester film for shaping | molding of 1st invention comprised from the copolyester comprised, or (b) aromatic dicarboxylic acid component containing terephthalic acid and isophthalic acid, and the glycol component containing ethylene glycol. to be.

The third invention is a laminated polyester film for molding according to the first invention, wherein the homopolyester is at least one member selected from the group consisting of polyethylene terephthalate, polytetramethylene terephthalate, and polybutylene terephthalate.

4th invention is 10-500 micrometers in total thickness of a laminated polyester film, and the thickness of B layer is 1 to 30% of the whole, The laminated polyester film for shaping | molding of 1st invention characterized by the above-mentioned.

In the fifth invention, the stress at 100% elongation of the laminated polyester film in the longitudinal direction and the width direction is both 40 to 300 MPa at 25 ° C and 1 to 100 MPa at 100 ° C. It is a laminated polyester film.

6th invention is a laminated polyester film for shaping | molding of 1st invention characterized by the haze of laminated polyester film being 2.0% or less.

7th invention is a laminated polyester film for shaping | molding which uses the laminated polyester film of 1st invention as a base material, and further laminate | stacks the coating layer (C layer) whose thickness is 0.01-5 micrometers on one or both surfaces of this base material. And the coating layer is a composition containing at least one resin and particles selected from polyester, polyurethane, acrylic polymer, or copolymers thereof, and the base material is substantially free of particles. Ester film.

8th invention is the process of manufacturing the unstretched sheet which laminated | stacks polyester B layer on the single side | surface or both sides of polyester A layer using the coextrusion method, the process of biaxially stretching an unstretched sheet to a longitudinal direction and the width direction, As a manufacturing method of the laminated polyester film for shaping | molding which becomes a process of heat-processing, holding a biaxially stretched film with a clip,

Polyester constituting the A layer and B layer is a copolyester or a mixture of copolyester and homopolyester,

The heat treatment process has a heat treatment section of two or more stages, and the maximum heating rate in the heat treatment section is 10 to 30 ° C / sec, and the maximum heat treatment temperature is (melting point of layer A-10 ° C) to (melting point of layer A + 20 ° C). It is a manufacturing method of the shaping | molding laminated polyester film of 1st invention characterized by controlling.

In the ninth invention, when the lateral stretching and heat treatment are performed while retaining and retaining the film with a clip in the tenter, the vicinity of the clip is cooled using one or more of the methods (i) to (v) below, followed by tenter It is a manufacturing method of the shaping | molding laminated polyester film of 8th invention characterized by opening a film from a clip at an exit.

(i) How to install a heat shield on the clip

(ii) adding the clip cooling mechanism to the tenter

(iii) A method in which the cooling section after heat setting is set long and the entire film is sufficiently cooled.

(iv) increase the cooling efficiency by increasing the length of the cooling section and the number of compartments;

(v) Method of strengthening the cooling of the clip by using a type in which the return portion of the clip travels outside the furnace.

Effects of the Invention

The laminated polyester film for molding of the present invention has a skin layer (B layer) on one side or both sides of the core layer (A layer), the melting point of the skin layer is higher than the melting point of the core layer, and the core layer also has an orientation structure. Since the laminated structure is adopted, functions such as further improvement of chemical resistance and heat resistance and protection of the core layer can be imparted to the skin layer. Moreover, sufficient flexibility can be provided to a core layer (A layer), and moldability can be improved further. Moreover, biaxial stretching improves the thickness nonuniformity and expresses the function which improves the heat resistance and chemical-resistance by orientation crystallization. In addition, by making the melting point of the skin layer (B layer) relatively high and employing specific heat treatment conditions, the deterioration of the activity can be suppressed and the impact resistance can be improved. For this reason, when manufacturing a film continuously for a long time, productivity and quality stability can be further improved at the time of post-processing to a film (printing, lamination | stacking of a metal film, a metal oxide film, etc.), shaping | molding process, or the use of a molded article. .

By using the laminated polyester film for molding of the present invention, it is difficult to mold with a conventional biaxially oriented polyester film. Even in this case, a molded article having good finish can be obtained. In addition, these molding methods are advantageous in terms of economics in the production of molded articles because of low molding cost. Therefore, application to these molding methods can most effectively exhibit the characteristics of the laminated polyester film for molding of the present invention.

On the other hand, mold molding is disadvantageous in terms of economical efficiency due to the high cost of a mold and a molding apparatus, but has a feature that molded articles having a more complicated shape than those described above are molded with high accuracy. For this reason, when mold-molding using the laminated polyester film for shaping | molding used for this invention, compared with the conventional biaxially-oriented polyester type film, it can shape | mold at lower forming temperature, and the finish of a molded article A marked effect of improvement is expressed.

Therefore, the laminated polyester film for molding of the present invention is excellent in moldability at the time of heating molding, especially at low temperature and low pressure, and thus applies a broad molding method such as mold molding, pressure molding, and vacuum molding. can do. In addition, when the molded article molded in this manner is used in a room temperature atmosphere, it is not only excellent in elasticity and shape stability (heat shrinkage characteristic, thickness nonuniformity), but also excellent in transparency, solvent resistance and heat resistance, and also excellent in impact resistance, It is suitable as an interior or exterior material for home appliances, mobile phones, automobiles, or building materials.

Moreover, the shaping | molding laminated polyester film of this invention is suitable also as a shaping | molding material shape | molded using shaping | molding methods, such as press molding, laminate molding, in-molding molding, drawing molding, bending molding, in addition to the said shaping | molding method.

Best Mode for Carrying Out the Invention

First, the technical meaning of the characteristic value used for each invention and evaluation used in this invention is demonstrated. Next, the raw material used when manufacturing the laminated polyester film for shaping | molding of this invention, and the manufacturing method of a film are demonstrated.

(1) Heat shrinkage rate at 150 ° C. (HS150)

In the laminated polyester film for molding of the present invention, the heat shrinkage ratio (HS150) at 150 ° C. is preferably 6.0% or less in both the longitudinal direction and the width direction. 5.0% of an upper limit of HS150 is more preferable, More preferably, it is 4.0%, Especially preferably, it is 3.0%. On the other hand, the lower limit of HS150 is preferably 0.01%, more preferably 0.1%, particularly preferably 0.5% from the viewpoint of practical use. Although HS150 is preferably small, the appropriate management criteria may be determined from the viewpoint of practical effects and productivity in accordance with the heat treatment temperature during the post-processing of the molding film and the temperature atmosphere in which the molded article is used. However, even when the film which HS150 is less than 0.01% is manufactured, a remarkable difference is not seen in practical effect. On the contrary, since the productivity is very low, there is no necessity of making HS150 less than 0.01%.

On the other hand, by making HS150 in the longitudinal direction and the width direction of the film 6.0% or less, deformation of wrinkles and the like of the film can be suppressed in the post-treatment step subjected to heat such as vapor deposition, sputtering or printing. As a result, the appearance and design of the film after the post-processing can be maintained in a good state. In addition, it is possible to suppress printing misalignment due to heating at the time of molding and to suppress distortion of the molded article when the molded article is exposed to a high temperature atmosphere. For this reason, it becomes possible to use a molded article in a wide temperature range.

(2) Thickness variation rate in the width direction

In this invention, the thickness variation rate of a film is used as a characteristic value regarding macro impact resistance.

Thickness variation (thickness nonuniformity) of a film is generally used as one of the characteristic values which show the quality of a film external appearance generally. When the thickness variation rate of a film is large, it means that the physical property which affects the thickness of a film fluctuates. If the thickness variation rate of a film becomes large, impact resistance will fall in a thin part. For this reason, when the film is continuously produced for a long time, tearing of the film occurs in a thin part during post-processing to the film (printing, lamination of a metal film or metal oxide film, etc.), during molding, or when using a molded article. It becomes easy to do it. Moreover, when shape | molding a film, a deformation | transformation of a film becomes nonuniform and stability falls, for example, non-uniformity of moldability.

Impact resistance can be improved by making the thickness variation rate of a film into 10% or less in the width direction. For this reason, the frequency at which the film is torn can be reduced at the time of continuous manufacture of the film, at the time of post-processing, at the time of molding, or at the time of use of the molded article. The thickness variation in the longitudinal direction is equally important, but in the present invention, the thickness variation in the width direction is used as a representative.

(3) 100% elongation stress (F100)

In the present invention, the stress at 100% elongation (F100) is a measure closely related to the formability of the film. As a reason why F100 is closely related to the formability of the film, for example, when forming a biaxially oriented polyester film using the vacuum forming method, the film may be locally stretched to 100% or more near the corner of the mold. . In the film with high F100, since the stress required for deformation | transformation is too high, it becomes inferior to deformation, and it is thought that moldability falls. On the other hand, in a film in which F100 is too small, it becomes deformable by low stress. However, only very weak tensions occur. For this reason, uniform elongation of the film in this part cannot be obtained and it is estimated that distortion generate | occur | produces in shaping | molding.

For this reason, in the present invention, 100% elongation stress at 100 ° C. (F100 ₁₀₀ ) is used as physical properties related to moldability corresponding to the temperature at the time of molding. In addition, the metal mold | die for shaping | molding may be used at the temperature of room temperature vicinity, and it is calculated | required that the F100 value is not too large also in the room temperature vicinity. Therefore, 100% elongation stress (F100 ₂₅ ) at 25 ° C is used as physical properties related to moldability at around room temperature.

As for the polyester film for shaping | molding in this invention, it is preferable that all the stress (F10025) at 100% elongation in ₂₅ degreeC of the longitudinal direction and the width direction of a film are 40-300 Mpa.

F100 in the longitudinal direction and the width direction of the film _25, the lower limit is more preferably 50 ㎫, and particularly preferably from 6.0 ㎫. On the other hand, 250 Mpa is more preferable, More preferably, it is 200 Mpa, Especially preferably, it is 180 Mpa. By setting F100 ₂₅ to 40 Mpa or more, when unrolling a roll-shaped film, elongation and tear of a film can be prevented and workability becomes favorable. On the other hand, by the F100 ₂₅ to less than 300 ㎫, the moldability becomes good.

In addition, it is preferable that the polyester film for shaping | molding in this invention is 1-100 Mpa of all 100% elongation stress at ₁₀₀ degreeC in ₁₀₀ degreeC of the longitudinal direction and the width direction of a film.

90 MPa is more preferable from a viewpoint of moldability, 80 MPa is further more preferable, and 70 Mpa is especially preferable in the upper limit of F100 ₁₀₀ in the longitudinal direction and the width direction of a film. On the other hand, the lower limit of F100 ₁₀₀ is more preferably 5 MPa, even more preferably 10 MPa, and particularly preferably 20 MPa from the viewpoint of elasticity and form stability when using a molded article.

(4) haze

It is preferable that haze is 2% or less of the laminated polyester film for shaping | molding of this invention. When the haze is 2% or less, the vividness and high quality of various kinds of decoration such as printing, metal deposition, sputtering layer and transfer layer are increased, and the product value can be significantly increased. The haze is more preferably 1.8% or less, particularly preferably 1.6% or less.

(5) Elongation at break at 25 ° C. (TE ₂₅ )

In the evaluation of the film of the present invention, the elongation at break at 25 ° C. is a characteristic value related to the handleability near the room temperature of the film. For example, by managing the elongation at break at 25 ° C., the permeability of post-processing such as printing and slits can be maintained in a good state.

Lamination

The laminated polyester film for molding of the present invention is a biaxially oriented laminated polyester film obtained by laminating a polyester B layer (skin layer) on one side or both sides of a polyester A layer (core layer).

That is, the laminated structure of the laminated polyester film of this invention has a basic structure based on 2 types 3 layers of B / A / B, or 2 types 2 layers of B / A. Moreover, an application layer (C layer) can be provided in at least one side of this base material as a base material, in order to provide quality improvement or another function to one side or both sides of the film of this invention.

In the laminated polyester film for molding of the present invention, both the A layer and the B layer are composed of copolyester or copolyester and homopolyester, and the melting point (TmA: ° C) of the A layer and the B layer. Melting | fusing point (TmB: degreeC) satisfy | fills following formula (1) and (2) simultaneously.

That is, in this invention, the skin layer (B layer) which becomes polyester B of melting | fusing point higher than polyester A of a core layer (A layer) is laminated | stacked on one side or both sides of a core layer, and a core layer also has an orientation structure. to be. The reason for leaving the alignment structure in the core layer (Layer A) will be described later in detail.

In addition, it is important for the laminated polyester film for molding of the present invention to satisfy the following relational expression (1) when the melting point (° C) of the A layer is TmA and the melting point (° C) of the B layer is TmB. Melting | fusing point means the endothermic peak temperature at the time of melting detected at the time of 1st temperature rising of differential scanning calorimetry (DSC).

It is preferable to make TmA and TmB below 260 degreeC from the viewpoint of the moldability of the whole film. In addition, it is important to make TmB and TmA higher than 200 degreeC, in order to maintain the heat resistance of the whole film and to make small the thermal deformation at high temperature. It is preferable to make TmB and TmA higher than 205 degreeC, Especially preferably, it is higher than 210 degreeC.

In the present invention, it is important to make the melting point (TmB) of the skin layer (Layer B) larger than the melting point (TmA) of the core layer (Layer A) in terms of highly balanced flexibility and activity, chemical resistance and heat resistance.

In addition, it is important for the laminated polyester film for molding of the present invention to satisfy the following relational formula (2) when the melting point (° C) of the A layer is TmA and the melting point (° C) of the B layer is TmB.

When TmB-TmA is 50 degreeC or more, since the difference of melting | fusing point of A-layer and B-layer is too big | large, thermal contraction rate, flexibility, impact strength, aging stability, and processing stability cannot be satisfied highly. As for "TmB-TmA", less than 40 degreeC is preferable, More preferably, it is less than 35 degreeC. Moreover, when "TmB-TmA" is 5 degrees C or less, since the difference of melting | fusing point is too small, it becomes difficult to highly balance flexibility and activity, chemical resistance, and heat resistance. It is preferable to make "TmB-TmA" higher than 10 degreeC, Especially preferably, it is higher than 15 degreeC.

The polyester film obtained by using the copolyester containing 5-50 mol% of copolymerization components as a raw material like this invention has a slow crystallization rate and low crystallinity compared with a polyethylene terephthalate film etc. In addition, in order to reduce the surface orientation and the thermal contraction rate of 150 ° C., when the method of heat treatment at a higher temperature than that described in Patent Document 3 is used, the heat treatment is rapidly performed at a high temperature after the end of the stretching, so that it is determined in the heat treatment section. Mobility of the molecules constituting the material having low properties is increased. Therefore, the surface protrusion formed by the rise of the particles (particles in the biaxially oriented film or particles in the coating layer) in the stretching step is buried again in the heat treatment section, making it difficult to form irregularities on the surface of the film. For this reason, the activity of a film deteriorates and blocking and tearing occur easily when the external appearance at the time of winding up a film in roll shape, and the unwinding of the film wound up in roll shape. In order to avoid these problems, when the content of the particles is increased more than necessary, the transparency of the film is deteriorated.

In the present invention, in order to proceed with the crystallization of the film and at the same time to relax the orientation, a heat treatment process is divided into a multi-stage heat treatment section, and a manufacturing method using a heating rate of the heat treatment section is within a specific range. By using this method, before the particles are embedded in the film, the crystallization of the film can be promoted to some extent and the sinking of the particles can be suppressed. In addition, a film having a low heat treatment rate is obtained by increasing the heat treatment temperature to promote crystallinity. In addition, in terms of transparency, there is no need to contain the particles more than necessary.

There are a number of factors that determine the melting point (Tm) of polyester, but it is thought that Tm is determined by how the crystallinity of the main polyester is dispersed. That is, by blending a copolyester or copolymerizing a homopolyester with respect to the homopolyester which becomes a main body, the crystallinity of the polyester which becomes a main body can be reduced and a required Tm can be obtained.

Specifically, in the copolymerization, it becomes the melting point when completely randomly transesterified, and in the blend, the operating conditions of the extruder, the residence time in the melt line, the raw material composition, the molecular weight, the raw material moisture content, the additives such as a catalyst, the acid value, etc. The transesterification rate is determined. If all these factors are fixed, a fixed melting point can be obtained with good reproducibility, and if only one factor is changed, a transesterification rate will be obtained, and a melting point with good reproducibility under these conditions will be obtained.

(Proper manufacturing method of film)

In the laminated polyester film for molding of the present invention, the polyester used for the core layer (A layer) and the skin layer (B layer) uses a copolyester or a blend of copolyester and homopolyester.

The copolyester includes (a) an aromatic dicarboxylic acid component, a copolymerized polyester composed of an ethylene glycol and a glycol component containing a branched aliphatic glycol or an alicyclic glycol, or (b) terephthalic acid and isophthalic acid. Co-polyester comprised from the aromatic dicarboxylic acid component and the glycol component containing ethylene glycol is suitable.

When the copolymerization component of said copolymerized polyester is branched aliphatic glycol or alicyclic glycol, the molecular structure of this glycol is large and molecular mobility at high temperature can be suppressed. For this reason, the film using co-polyester containing a branched aliphatic glycol or alicyclic glycol as a copolymerization component improves heat resistance. On the other hand, heat resistance improves also when the dicarboxylic acid component of a copolymerization component becomes only an aromatic dicarboxylic acid component.

In addition, it is preferable that the polyester constituting the biaxially oriented polyester film further contains 1,3-propanediol units or 1,4-butanediol units as glycol components in terms of further improving moldability. In addition, by introducing these units into the copolyester, microcrystals are formed in the molecule, for example, it is possible to suppress a decrease in the elastic modulus at 180 ° C. These units may be introduced as a copolymerization component of the copolyester, or a method of blending homopolyesters such as polytrimethylene terephthalate (PTT) and polybutylene terephthalate (PBT) may be used.

In this invention, as a film raw material, any method of a copolyester alone, a blend with 2 or more types of copolyesters, or a blend of 1 or more types of homopolyesters and 1 or more types of copolyesters is possible. Among these, a blend of homopolyester and copolyester is suitable in view of suppressing a decrease in melting point.

As said copolyester, when using the copolyester comprised from the aromatic dicarboxylic acid component, ethylene glycol, and the glycol component containing a branched aliphatic glycol or alicyclic glycol, as an aromatic dicarboxylic acid component, Terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid or ester-forming derivatives thereof are suitable. The amount of terephthalic acid units and / or 2,6-naphthalenedicarboxylic acid units relative to the total dicarboxylic acid component is at least 70 mol%, preferably at least 85 mol%, more preferably at least 95 mol%, particularly preferably Is 100 mol%. The molar ratio of the terephthalic acid unit and the 2,6-naphthalenedicarboxylic acid unit is preferably 100/0 to 50/50.

In addition, examples of the branched aliphatic glycol include neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and the like. As alicyclic glycol, 1, 4- cyclohexane dimethanol, tricyclodecane dimethylol, etc. are illustrated.

Among these, neopentyl glycol and 1, 4- cyclohexane dimethanol are especially preferable. It is preferable to use these glycols as a copolymerization component in order to provide the said characteristic, and also to be excellent in transparency and heat resistance, and to improve adhesiveness with the coating layer at the time of providing an application layer.

In addition, when using the copolymer polyester which consists of the aromatic dicarboxylic acid component containing terephthalic acid and isophthalic acid, and the glycol component containing ethylene glycol as said copolyester, the quantity of ethylene glycol is the total glycol component. At least 70 mol%, preferably at least 85 mol%, particularly preferably at least 95 mol%, most preferably 100 mol%. As glycol components other than ethylene glycol, said branched aliphatic glycol, alicyclic glycol, or diethylene glycol is suitable. In addition, the molar ratio of the terephthalic acid unit and the isophthalic acid unit is preferably in the range of 100/0 to 50/50.

As a catalyst used when producing the above-mentioned copolyester, for example, an alkaline earth metal compound, a manganese compound, a cobalt compound, an aluminum compound, an antimony compound, a titanium compound, a titanium / silicon composite oxide, a germanium compound, or the like can be used. have. Among these, a titanium compound, an antimony compound, a germanium compound, and an aluminum compound are preferable in terms of catalytic activity.

When producing said copolyester, 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.

In view of moldability and film forming stability, 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 0.60 dl / g or more. If the intrinsic viscosity is less than 0.50 dl / g, the moldability tends to be lowered. On the other hand, in terms of impact resistance, by setting the intrinsic viscosity of the film to 0.60 dl / g or more, the impact strength of the film is improved, and the frequency of breakage at the time of film forming and processing of the film can be reduced. In addition, when a filter for removing foreign matters is provided in the melt line, it is preferable to set the upper limit of the intrinsic viscosity to 1.0 dl / g in view of the discharge stability during extrusion of the molten resin.

In the present invention, by using at least one homopolyester and at least one copolyester as a film raw material and blending them to form a film, transparency and high melting point (while maintaining the same flexibility as in the case of using only copolyester) Heat resistance) can be realized. In addition, when only homopolyester (for example, polyethylene terephthalate) which is high melting | fusing point is used, melting | fusing point (heat resistance) which has high transparency and no practical problem can be implement | achieved.

In addition, the copolymerized polyester and homopolyesters other than polyethylene terephthalate (for example, polytetramethylene terephthalate or polybutylene terephthalate) are blended and blended with each other to form the laminated polyester film for molding of the present invention. It is more preferable to use it as a raw material from a moldability viewpoint.

Moreover, you may use together 1 type (s) or 2 or more types as a copolymerization component with the following dicarboxylic acid components and / or glycol components to the said copolymer polyester as needed.

As another dicarboxylic acid component which can use together terephthalic acid or its ester-forming derivative, (1) isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'- dicarboxylic acid, Aromatic dicarboxylic acids or ester-forming derivatives thereof such as diphenoxyethane dicarboxylic acid, diphenylsulfondicarboxylic acid, 5-sodium sulfoisophthalic acid and phthalic acid, (2) oxalic acid, succinic acid, adipic acid, Aliphatic dicarboxylic acids or ester-forming derivatives thereof such as sebacic acid, dimer acid, maleic acid, fumaric acid and glutaric acid, and (3) cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid or their ester-forming properties Derivatives, (4) oxycarboxylic acids such as p-oxybenzoic acid and oxycaproic acid or ester-forming derivatives thereof; and the like can be given.

On the other hand, other glycol components that can be used together with ethylene glycol and branched aliphatic glycols and / or alicyclic glycols include, for example, aliphatic glycols such as pentanediol and hexanediol, aromatic glycols such as bisphenol A and bisphenol S; These ethylene oxide addition products, diethylene glycol, triethylene glycol, etc. are mentioned.

In addition, it is also possible to copolymerize polyfunctional compounds, such as trimellitic acid, trimesic acid, and trimethylolpropane, in addition to the said copolyester as needed.

Moreover, it is preferable to form an unevenness | corrugation in the film surface for the improvement of the handling property, such as activity of a film and winding property. Generally as a method of forming an unevenness | corrugation on a film surface, the method of containing particle | grains in a film is used.

However, since the particle | grains contained in a film generally have a refractive index different from polyester, it becomes a factor which reduces the transparency of a film. In order to improve designability, a molded article is often printed on the film surface before shape | molding a film. Since such a printed layer is often performed behind a shaping | molding film, it is desired to have high transparency of a film from the viewpoint of print definition.

Therefore, in the present invention, it is preferable to adopt the following two configurations in order to improve transparency. The 1st structure makes the thickness of the skin layer (layer B) of a laminated polyester film 1-5 micrometers, and contains particle | grains only in this skin layer (layer B), and contains a particle | grain substantially in a core layer (layer A). It is not a configuration. 2nd structure is based on laminated polyester film, and further laminate | stacks the coating layer (C layer) whose thickness is 0.01-5 micrometers on one or both surfaces of this base material, and a coating layer is polyester, a polyurethane, and an acrylic polymer. Or a composition containing at least one resin and particles selected from their copolymers, and the substrate is substantially free of particles. 3 micrometers is preferable and, as for the upper limit of the thickness of the surface layer which contains the said particle | grains, 1 micrometer is especially preferable. Moreover, the method of using a coating layer (C layer) has the advantage that it is excellent also in adhesiveness with a printing layer in addition to providing transparency and activity.

In addition, the above-mentioned "it does not contain particle | grains substantially in a base film" means content which becomes below a detection limit, for example, in the case of an inorganic particle, when quantifying an inorganic element by fluorescent X-ray analysis. This is because contaminants derived from foreign foreign substances and the like may be mixed without consciously adding particles to the base film.

As said particle | grain, external particle | grains, such as well-known internal particle, inorganic particle, and / or organic particle | grains whose average particle diameter (average particle diameter on the basis of number by SEM) are 0.01-10 micrometers, are mentioned. When the particle | grains whose average particle diameter exceeds 10 micrometers are used, defects of a film tend to arise and designability tends to deteriorate. On the other hand, in the particle | grains whose average particle diameter is less than 0.01 micrometer, there exists a tendency for handling property, such as activity and the winding property of a film, to fall.

In addition, the average particle diameter of a particle | grain is computed by taking a plurality of photographs of the at least 200 particle | grains by the electron microscope method, trace the outline of particle | grains on an OHP film, and converting this trace image into the equivalent circle diameter with an image analyzer.

Examples of the external particles include inorganic and styrene such as wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, hydroxyapatite, and the like. Organic particles etc. which consist of silicone, acrylic acids, etc. can be used. Among them, 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 are preferably used. In addition, silica particles, glass fillers, and silica-alumina composite oxide particles are particularly suitable in terms of transparency because the refractive index is relatively close to polyester. These internal particles, inorganic particles and / or organic particles may be used in combination of two or more within a range that does not impair the characteristics.

In addition, it is adjusting content of the particle | grains in the layer containing the said particle | grains in 0.001-10 mass% in the range in which the haze of a laminated film is 2.0% or less, and the activity and the coilability of a film do not become a problem. desirable.

It is important that the laminated polyester film for molding of the present invention is a biaxially stretched film. In the present invention, solvent alignment and dimensional stability, which are disadvantages of the unstretched sheet, are improved by molecular orientation by biaxial stretching. That is, it is one of the characteristics of this invention to improve the solvent resistance and heat resistance which are the drawbacks of an unstretched sheet, maintaining the advantage of the moldability of an unstretched sheet.

As a manufacturing method of a laminated biaxially-oriented polyester film, the following method is used, for example. The polyester using the polyester A layer and the polyester B layer is dried, and then separately supplied to two or more melt extruders, and laminated by B / A or B / A / B in the molten state by the coextrusion method. They are extruded from the slit-shaped die into sheets, adhered to the casting drum by electrostatic application or the like, and cooled and solidified to obtain an unstretched sheet. Next, the method of biaxially stretching this unstretched sheet is illustrated. In addition, when using a vented extruder, drying of a film raw material chip is not necessarily required.

In the coextrusion process, the melt extrusion conditions are appropriately adjusted in accordance with the raw materials used for each of the A and B layers, and the conditions for adjusting the melting point of the film within the appropriate range are selected while suppressing the progress of hydrolysis and thermal degradation. do. In the case of a raw material having a melting point, the extrusion temperature is set to (melting point + 100 ° C) or lower, preferably (melting point + 90 ° C) or lower, more preferably (melting point + 80 ° C) or lower, and decomposition and melting point drop are suppressed. do. The residence time to the die exit is also 20 minutes or less, preferably 18 minutes, more preferably 16 minutes or less to suppress decomposition and melting point drop.

The melt-extruder used for A-layer and B-layer uses the extruder which has a feed part, a compression part, a metering part, and a melt line part, for example.

Further, in the melt extruder, the resin is gradually heated up from the feed portion to the compression portion, the upper limit of the resin temperature is controlled in the above range, and is completely melted. In addition, in a metering part and a melt line part, in order to suppress the fall of film intrinsic viscosity, it is preferable to make resin temperature below 280 degreeC in resin for core layers (A layer), for example. In particular, in the melt line portion, in order to suppress the progress of the resin deterioration, the temperature is preferably 275 ° C or lower, more preferably 270 ° C or lower.

As a biaxial stretching method, the unstretched sheet is stretched and heat-treated in the longitudinal direction (MD) and the width direction (TD) of a film, and the method of obtaining the biaxially stretched film which has a target physical property is employ | adopted. Among these methods, sequential biaxiality such as the MD / TD method stretching in the longitudinal direction after stretching in the longitudinal direction from the aspect of film quality or the TD / MD method stretching in the longitudinal direction after stretching in the width direction. The simultaneous biaxial stretching method of stretching the stretching method, the longitudinal direction and the width direction at about the same time is preferable. In the case of the simultaneous biaxial stretching method, a tenter driven by a linear motor may be used. In addition, you may use the multistage extending | stretching method which divides extending | stretching of the same direction into multiple steps and performs as needed.

It is preferable that it is 1.6-4.2 times in the longitudinal direction and the width direction at the time of biaxial stretching, Especially preferably, it is 1.7-4.0 times. In this case, the stretching magnification in the longitudinal direction and the width direction may be increased, or may be the same magnification. As for the draw ratio of the longitudinal direction, it is more preferable to carry out by 2.8 to 4.0 times, and the draw ratio of the width direction to 3.0 to 4.5 times.

In extending | stretching of a longitudinal direction, it is preferable to make extending | stretching temperature 50-110 degreeC, and draw ratio 1.5-4.0 times so that extending | stretching of the later width direction may become smooth.

Usually, when extending | stretching polyethylene terephthalate, when extending | stretching temperature is low compared with suitable conditions, extending | stretching stress rises rapidly at the beginning of a lateral stretch, and extending | stretching is impossible. Moreover, even if extending | stretching is possible, since thickness and draw ratio are easy to become nonuniform, it is unpreferable. Therefore, in the present invention, it is preferable to adopt the following stretching conditions.

First, it is preferable to make preheating temperature into 90-140 degreeC. Next, in the first half of the stretching in the width direction, the stretching temperature is preferably -10 to 25 ° C with respect to the preheating temperature, and particularly preferably -10 to 20 ° C. In addition, in the latter part of the widthwise stretching, the stretching temperature is preferably 0 to + 20 ° C, particularly preferably +5 to + 20 ° C, relative to the stretching temperature of the first half. By adopting such conditions, the stretching stress becomes relatively large in the first half of the stretching in the width direction, thereby enabling uniform stretching. In the latter half, the stretchability is improved by increasing the temperature. In addition, the draw ratio in the width direction is preferably 2.5 to 5.0 times.

Moreover, the film is heat-treated after biaxial stretching. This heat treatment can be performed by a conventionally well-known method, such as a tenter or a heated roll shape. The heat treatment temperature and heat treatment time can be arbitrarily set according to the level of heat treatment rate required.

In the present invention, the heat treatment step is performed in a heat treatment section of two or more stages, the maximum heating rate in the heat treatment section is 10 ~ 30 ℃ / sec, the maximum heat treatment temperature (melting point of layer A-10 ℃) ~ (melting point of layer A + 20 Is preferably controlled. Moreover, it is more preferable that a heat processing area is three or more sections, and 4 or more sections are especially preferable. Although an appropriate range is determined according to the feeding speed of a film and the length of a heat processing process, it is preferable to carry out for 1 to 60 second, for example. In addition, you may perform this heat processing, relaxing a film to the longitudinal direction and / or the width direction.

In order to reduce the heat shrinkage rate at 150 ° C in the longitudinal direction and the transverse direction of the film, it is preferable to increase the heat treatment temperature, lengthen the heat treatment time, and perform relaxation treatment. Specifically, in order to make the thermal contraction rate at 150 ° C in the longitudinal direction and the width direction of the film at 6.0% or less, the maximum heat treatment temperature in the heat treatment step is (melting point of layer A-10 ° C) to (melting point of layer A + 20 degreeC), and it is preferable to carry out, relaxing at 1-8% of relaxation rate. In addition, redrawing may be performed once or more in each direction, and heat processing may be performed after that.

The upper limit of the maximum heat treatment temperature in the heat treatment step is preferably (melting point of layer A + 15 ° C), more preferably (melting point of layer A + 10 ° C), particularly preferably, in order to leave the alignment structure in the layer A. Preferably (melting point of layer A + 5 ° C.). In addition, this heat processing temperature is a preset temperature, and is not a room temperature of a film.

However, it is difficult to lengthen the production line to lengthen the heat treatment time due to equipment limitations. Moreover, when the sending speed of a film is made slow, productivity will fall. As described above, the film is heated at a relatively low temperature of about 100 ° C. to the drawing section in the tenter, but the film passing through the drawing section enters the heat treatment section and needs to be rapidly heated to a high temperature around 200 ° C. Therefore, it is recommended as a preferred embodiment to install a far-infrared heater in the heat treatment section and to reinforce the heating of the film.

For example, it is preferable to use a method of providing a heat insulation section of 1 m or more between the stretching section and the heat treatment section and increasing the heating efficiency thereafter. In other words, the heating effect is enhanced by reinforcing the partitions for each section to reduce the leakage of heat flow. By adjusting the balance and strength of the air volume, the pressure in the tenter can be adjusted while ensuring the air volume, and leakage of heat flow can be suppressed. In addition, it is preferable to add an infrared heater to the strong heating section for the heating which is insufficient in the hot air heating furnace. In addition, a method of increasing the amount of heating by increasing the length and number of sections of the heat setting section is also effective.

In addition, when the film thickness is 50 µm or less, the maximum heat treatment temperature of the heat treatment section is lower than or equal to (melting point of layer A-10 ° C) or higher (melting point of layer A + 20 ° C) or lower at a low temperature around 100 ° C after finishing stretching. When the temperature is rapidly raised to the range, the following problem occurs.

That is, in the laminated | multilayer film of this invention, since the copolyester is used, crystallinity is low. For this reason, in addition to the deterioration of the thickness nonuniformity of a film in a heat processing area and a fall of impact strength, a hole may arise in a film in a heat processing area during film forming, and continuous film forming may not be possible.

In order to solve this problem, it is important to gradually increase the temperature in the heat treatment section, to promote the crystallization of the film, and to relax the orientation of the film by the heat treatment. Specifically, when manufacturing the laminated film of the present invention, it is important to raise the temperature stepwise so that the temperature increase rate in the heat treatment section is 10 to 30 ° C / sec. The temperature increase rate in the heat treatment section is preferably 15 ~ 25 ℃ / sec.

In addition, if the temperature increase rate of the heat treatment section is too fast, the film crystallizes before the orientation of the film by heat treatment is relaxed. For this reason, the polyester which comprises a film falls, not only the impact strength of a film falls, but a hole arises in a film in the heat processing section during film forming, and continuous film forming becomes difficult. On the other hand, if the temperature increase rate of the heat treatment section is too slow, the film passes through the heat treatment section before reaching the required maximum heat treatment temperature due to the constraints on the equipment. For this reason, the thermal contraction rate of the film in the longitudinal direction and the width direction in 150 degreeC becomes large by lack of heat processing temperature.

Moreover, in order to satisfy the characteristic of the film prescribed | regulated by this invention simultaneously, it is also preferable to suppress the fall of film intrinsic viscosity. In order to maintain the intrinsic viscosity of the film at 0.50 dl / g or more, for example, it is preferable to employ the above-described temperature conditions during melt extrusion. Moreover, it is also preferable to suppress the fall of the intrinsic viscosity by polyester hydrolysis at the time of melt extrusion by reducing the moisture content of polyester which is a raw material.

In addition, what is necessary is just to set the total thickness of the laminated polyester film of this invention suitably in the range of 10-500 micrometers according to a use. Generally, the thickness of a film is used in the range which is 20-188 micrometers in many cases. Moreover, it is preferable that the thickness of B layer exists in 1 to 30% of range of a total thickness, More preferably, it is 2 to 27%, More preferably, it is 3 to 25% of range. Since the thickness of B-layer is 1% or more of total thickness, the fall of chemical-resistance and heat resistance by B-layer can be prevented. Moreover, film forming stability is also excellent. On the other hand, since the thickness of B-layer is 30% or less of total thickness, deterioration of moldability and thermal contraction rate can be suppressed.

In order to improve the moldability of a film, the method of reducing surface orientation is generally used. For example, a method of lowering the draw ratio is known as a means for lowering the plane orientation. However, this method worsens the thickness nonuniformity of the film. On the other hand, in the present invention, the heat treatment temperature is higher than usual, and the temperature increase rate in the heat treatment section is controlled to a certain range, thereby growing the crystals of the film and using the method of relaxation of the orientation.

In the present invention, by devising the heat treatment temperature using the above technique, the required physical properties are produced, but if the heat treatment temperature is too high, the core layer is unoriented, and many defects occur.

(1) By lowering the elongation at break at room temperature, it becomes a very soft film, so that winding and slits in the manufacturing process are difficult.

(2) Since it is easy to break even at the time of use, a problem occurs in handling.

(3) The thickness nonuniformity becomes very bad, and the handleability, the appearance quality fall, processing quality, and work reproducibility deteriorate.

(4) At the time of shaping | molding, at the time of post-processing with heating, such as printing, or when using a molded article in high temperature atmosphere, an unoriented part may turn white by heating, and an appearance becomes bad. For this reason, the temperature range at the time of use or processing will be limited.

To avoid these problems, the core layer should not be made unoriented by selecting an appropriate heat treatment temperature.

In addition, since the melting point of the copolyester used as a raw material of the film in the present invention is lower than that of the homopolymer, when the heat treatment temperature is increased, the film adheres to the clip holding and holding the film in the tenter, making it difficult to peel off. There is. Therefore, when the clip opens the film at the tenter exit, it is important to sufficiently cool the vicinity of the clip when continuous film forming.

Specifically, in order to prevent adhesion between the film and the clip, (1) a method of providing a heat shield wall in the clip portion so that the clip is hard to heat, (2) a method of adding a clip cooling mechanism to the tenter, and (3) In order to enhance the cooling capacity, the cooling section after heat setting is set long to sufficiently cool the entire film, (4) the cooling efficiency is increased by increasing the length and the number of sections of the cooling section, and (5) It is preferable to employ a method of enhancing cooling of the clip by using a type of traveling outside the furnace on the clip return portion.

Hereinafter, the present invention will be described in detail by way of examples. In addition, the film characteristic obtained by each Example was measured and evaluated by the following method.

(1) intrinsic viscosity

0.1 g of the chip samples were precisely weighed, dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 6/4 (mass ratio), and measured at 30 ° C using an Ostwald viscometer. In addition, the measurement was performed 3 times and the average value was calculated | required.

(2) melting point of film

Using a differential scanning calorimeter (manufactured by DuPont, V4 OB2000), a sample amount of about 0.010 g, a measurement temperature range of 300 ° C at room temperature, and a temperature increase rate of 20 ° C / min were measured. Melting | fusing point determination of A-layer and B-layer cut | disconnects a film in A4 size, and adhere | attaches it to a flat plate, and cuts off the surface using one blade razor, and measures melting | fusing point of B-layer by performing DSC measurement. Next, melting | fusing point of the whole film was calculated | required by DSC measurement, and melting | fusing point of A-layer was calculated | required by excluding the information of the melting peak regarding melting | fusing point of B-layer.

(3) presence or absence of A layer (core layer) orientation

Preparation of the sample for determination produces a thin section (thickness: 10 micrometers) for permeation | transmission observation of the cross section in a thickness direction parallel to the MD direction of a film using a microtome. Subsequently, the brightness of the image in A-layer in the case of rotating a polarizing plate using a transmission type polarizing microscope is visually determined on the following reference | standard. In addition, the magnification was 200 times.

No orientation: The brightness of the image in layer A does not substantially change.

With orientation: The brightness of the image in layer A changes.

(4) film thickness

It measured according to JIS K 7105 "Plastic-film and sheet-thickness measuring method" the measuring method by mechanical scanning (A method). The measuring device used the electron micrometer (Maritron 1240 made by Marsa). The thickness of the film measured 5 points per film and 3 pieces of 15 pieces in total, and calculated | required the average value.

(5) Stress at 100% elongation (F100) and elongation at break (TE)

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

In addition, the measurement was performed in 25 degreeC atmosphere on the conditions of 40 mm of initial lengths, 100 mm of chuck | zipper distances, 100 mm / min of a crosshead speed, 200 mm / min of chart speed of a recorder, and 25 kgf of load cells. 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 above even under an atmosphere of 100 ° C. At this time, the sample was measured after maintaining for 30 second in 100 degreeC atmosphere. In addition, the measurement was performed 10 times and the average value was used.

(6) heat shrinkage at 150 ° C

Based on JIS C 238-1997 5.3.4 (dimension change), the thermal contraction rate in 150 degreeC of the longitudinal direction and the width direction of a film was measured in the following procedure.

The rectangular sample of length 250mm and width 20mm is cut out with respect to the longitudinal direction and the width direction of a film, respectively. Two marks are made at 200 mm intervals in the longitudinal direction of each sample, and the distance A between the two marks is measured under a constant tension of 5 g (tension in the longitudinal direction). Subsequently, one side of each rectangular sample is hung with a clip on a basket under no load, placed in a gear oven under a 150 ° C atmosphere, and the time is measured. After 30 minutes, the basket is taken out of the gear oven and left to stand at room temperature for 30 minutes. Subsequently, for each sample after the heat treatment, the interval B (the interval between the two marks after the heat treatment) of the two marks under a constant tension of 5 gf (tension in the longitudinal direction) is read out by a steel ruler in 0.25 mm units. . From the space | interval A and B which were read, the thermal contraction rate in 150 degreeC of each sample was computed by the following formula, and was judged by the following reference | standard. The measurement was performed 3 times and the average value was calculated | required. The figure is rounded to the second digit after the decimal point, to one digit after the decimal point.

(7) Thickness variation rate in the width direction

A sample on a continuous tape of 3 m in the width direction and 5 cm in the longitudinal direction is wound on the film, the thickness of the film is measured by a film thickness continuous measuring instrument (manufactured by Anritsu Co., Ltd.), and recorded in a recorder. The maximum value dmax, the minimum value dmin, and the average value d of thickness were calculated | required from the chart, and the thickness variation rate (%) was computed by the following formula. In addition, the measurement was performed 3 times and the average value was calculated | required. In addition, when the length of the width direction is less than 3 m, it connects and performs. Also, the seam portion is deleted from the data.

(8) haze

Based on JIS K 7136, it measured using the haze meter (300A of Nippon Denshoku Industrial Co., Ltd. make). In addition, the measurement was performed twice and the average value was calculated | required.

(9) impact strength

Using a film impact tester (manufactured by Toyo Seiki Co., Ltd., T-84-3), the measuring film was pressed down with a clamp, and the impact strength of the sample was measured by deeply punctured with a hemisphere impact head having a diameter of 1/2 inch. The sample was cut out to 100 mm x 100 mm or more, and the ring which fixed the sample was 30 mm inside diameter. In addition, the measurement was performed 10 times and the average value was calculated | required. The average value was calculated | required per thickness 1mm, it was calculated | required as the impact strength (J / mm) of a film, and it determined by the following references | standards.

(10) formability

(a) vacuum formability

After 5 mm square printing was performed on the film, the film was heated for 10 to 15 seconds with an infrared heater heated to 500 ° C, and vacuum molding was performed at a mold temperature of 30 to 100 ° C. In addition, the heating conditions selected the optimum conditions within the said range about each film. The shape of the mold was cup-shaped, the opening was 50 mm in diameter, the bottom part was 40 mm in diameter, 50 mm in depth, and all corners were curved to 0.5 mm in diameter.

The moldability and the finishability were evaluated about five molded articles vacuum-molded under optimal conditions, and the ranking was performed based on the following reference | standard. In addition, (circle) and (circle) were made pass and x was rejected.

(Double-circle): (i) There is no tear in a molded article,

(ii) the radius of curvature of the corner is 1 mm or less, and the printing deviation is 0.1 mm or less,

(iii) also without appearance defects corresponding to x

○: (i) there is no tear in the molded article,

(ii) the radius of curvature of the corner is more than 1 mm and 1.5 mm or less, or the printing deviation is more than 0.1 mm and 0.2 mm or less,

     (iii) also at a level having no appearance defects corresponding to x and having no practical problem.

X: The thing corresponded to any one of the following items (i)-(iv) even if there exists a tear in a molded article, or there is no tear

(i) The radius of curvature of the corners exceeds 1.5 mm

(ii) bad appearance due to large wrinkles

(iii) whitening of the film lowers transparency

(iv) the deviation of printing exceeds 0.2 mm

(b) pressure forming ability

After 5 mm square printing was performed on the film, the film was heated by an infrared heater heated to 500 ° C for 10 to 15 seconds, and the mold temperature was 30 to 100 ° C, followed by pressure forming at 4 atmospheres. In addition, the heating conditions selected the optimal conditions within the said range about each film. The shape of the mold was cup-shaped, the opening was 60 mm in diameter, the bottom was 55 mm in diameter, 50 mm in depth, and all corners were curved to 0.5 mm in diameter.

The moldability and the finishability were evaluated about five molded articles press-molded under optimal conditions, and the ranking was performed based on the following reference | standard. In addition, (circle) and (circle) were made pass and x was rejected.

(Double-circle): (i) There is no tear in a molded article,

(ii) the radius of curvature of the corner is 1 mm or less, and the printing deviation is 0.1 mm or less,

(iii) also without appearance defects corresponding to x

○: (i) there is no tear in the molded article,

(ii) the radius of curvature of the corner is more than 1 mm and 1.5 mm or less, or the printing deviation is more than 0.1 mm and 0.2 mm or less,

(iii) also at a level having no appearance defects corresponding to x and having no practical problem.

X: The thing corresponded to any one of the following items (i)-(iv) even if there exists a tear in a molded article, or there is no tear

(i) The radius of curvature of the corners exceeds 1.5 mm

(ii) bad appearance due to large wrinkles

(iii) whitening of the film lowers transparency

(iv) the deviation of printing exceeds 0.2 mm

(c) mold formability

After printing to a film, after contact heating for 4 seconds with the hotplate heated at 100-140 degreeC, press molding was performed at the mold temperature of 30-70 degreeC and holding pressure time 5 second. In addition, heating conditions selected the optimal conditions within the said range about each film. The shape of the mold was cup-shaped, the opening was 50 mm in diameter, the bottom was 40 mm in diameter, 30 mm in depth, and all corners were curved to 0.5 mm in diameter.

The moldability and the finishability were evaluated about five molded articles molded by the mold under optimal conditions, and the ranking was performed based on the following criteria. In addition, (circle) and (circle) were made pass and x was rejected.

(Double-circle): (i) There is no tear in a molded article,

(ii) the radius of curvature of the corner is 1 mm or less, and the printing deviation is 0.1 mm or less,

(iii) also without appearance defects corresponding to x

○: (i) there is no tear in the molded article,

(ii) the radius of curvature of the corner is more than 1 mm and 1.5 mm or less, or the printing deviation is more than 0.1 mm and 0.2 mm or less,

(iii) also at a level having no appearance defects corresponding to x and having no practical problem.

X: The thing corresponded to any one of the following items (i)-(iv) even if there exists a tear in a molded article, or there is no tear

(i) The radius of curvature of the corners exceeds 1.5 mm

(ii) bad appearance due to large wrinkles

(iii) whitening of the film lowers transparency

(iv) the deviation of printing exceeds 0.2 mm

(11) solvent resistance

A sample was immersed in toluene which adjusted temperature at 25 degreeC for 30 minutes, and it judged by the following reference | standard about the external appearance change before and behind immersion, and made (circle) the pass. In addition, haze value was measured by the said method.

○: almost no change in appearance and less than 1% change in haze value

X: Appearance change is recognized or the change of a haze value is 1% or more

(12) Static friction coefficient μs and dynamic friction coefficient μd

Based on JIS-C2151, it evaluated by the following conditions.

Test piece for flat plates: 130 mm in width, 250 mm in length, non-printed surface side

Cutting piece for cutting: 120 mm wide and 120 mm long

Atmosphere: 23 ℃, 50% RH

Shear Mass: 200 g

Test speed: 150 mm / min

The measured value was determined based on the following criteria.

○: less than 0.8 for both μs and μd

×: any one of μs and μd is 0.8 or more

(13) heating whitening

After heat-processing at 150 degreeC for 30 minutes, the external appearance observation was performed on the following references | standards. ○ is pass.

○: no change

X: The film is cloudy and a change is seen.

Example 1

(Preparation of Water Disperse Polyester Graft Copolymer)

75 mass parts of hydrophobic copolyester, 56 mass parts of methyl ethyl ketones, and 19 mass parts of isopropyl alcohol were put into the reactor provided with the stirrer, the thermometer, the reflux apparatus, and the quantitative loading apparatus, and it heated and stirred at 65 degreeC, and dissolved resin. . After the resin was completely dissolved, 15 parts by mass of maleic anhydride was added to the polyester solution. Next, the solution which melt | dissolved 10 mass parts of styrene and 1.5 mass parts of azobisdimethylvaleronitrile in 12 mass parts of methyl ethyl ketone was dripped at the polyester solution at 0.1 ml / min, and stirring was continued for 2 hours further. After performing analytical sampling from the reaction solution, 5 parts by mass of methanol was added. Subsequently, 300 mass parts of ion-exchange water and 15 mass parts of triethylamine were added to the reaction solution, and it stirred for 1 hour and a half. Then, the reactor internal temperature was raised to 100 degreeC, methyl ethyl ketone, isopropyl alcohol, and the excess triethylamine were distilled off, and the water-dispersed polyester graft copolymer was obtained. The obtained polyester graft copolymer was pale yellow transparent, and the glass transition temperature was 40 degreeC.

(Preparation of coating liquid a for printability improvement layer)

Polyester graft copolymer dispersed in a mixed solvent of ion-exchanged water and isopropyl alcohol (mass ratio: 60/40) such that the total solid concentration is 5% by mass, and styrene-benzo having an average particle diameter of 2.2 mu m as particles. Guanamine-based spherical organic particles (manufactured by Nippon Shokubai Industries Co., Ltd.) and colloidal silica (manufactured by Shokubai Kasei Co., Ltd.) having an average particle diameter of 0.02 µm were mixed so as to have a solid content mass ratio of 50/1/3, respectively, to prepare a coating solution A. .

(Preparation of coating liquid b for active improvement layer)

To a mixed solvent of ion-exchanged water and isopropyl alcohol (mass ratio: 60/40), the water-dispersible polyester copolymer (by Toyo Boseki Co., Vironal MD-16) so that the total solid concentration is 5% by mass , Sodium dodecyldiphenyl oxide disulfonic acid salt (made by Matsumoto oil and fat, anionic antistatic agent) as a sulfonic acid metal salt, polyethylene emulsion wax (manufactured by Toho Chemical Co., Ltd.) as a polymer wax, and styrene-benzoguanamine having an average particle diameter of 2.2 탆 as particles. System spherical organic particles (manufactured by Nippon Shokubai Industrial Co., Ltd.) and colloidal silica (manufactured by Nissan Chemical Co., Ltd.) having an average particle diameter of 0.04 µm were respectively mixed so as to have a solid content mass ratio of 50 / 2.5 / 2.5 / 0.5 / 5 to prepare a coating solution B. .

(Manufacture of Film Raw Material)

The resin of the composition of Table 1 was dried and used as a raw material of a core layer (A layer) and a skin layer (B layer).

(Manufacture of Laminated Film)

Using a co-extruder extruder having a feed block and a T die, the B-layer raw material was coextruded under the B-layer extrusion conditions of Table 2, and the A-layer raw material was co-extruded under the A-layer extrusion conditions of Table 2. The configuration of the layer is two or three layers of B / A / B. Moreover, the discharge amount of resin at the time of melt extrusion was adjusted so that final film thickness might be 100 micrometers, and the thickness of each layer might be a ratio of B / A / B = 8/84/8. The residence time of the skin layer (B layer) was 18 minutes, and the residence time of the core layer (A layer) was 8 minutes, and rapidly cooled on a cast drum having a surface temperature of 40 ° C to obtain an amorphous sheet.

The obtained sheet was stretched 3.3 times at 83 ° C. in the longitudinal direction between the preheat roll and the cooling roll by the rotation speed difference. The said coating liquid a was apply | coated to the single side | surface of the obtained uniaxial stretched film, and the coating liquid b was apply | coated to the other surface by the reverse coat method. Further, each coating liquid was subjected to a shear rate of 1000 (1 / second) or more between the roll gaps, and applied to the base film within 2 seconds, and dried for 2 seconds under an environment of 65 ° C, 60% RH, and a wind speed of 15 m / sec. . In addition, it is dried for 3 seconds in an environment of 130 ° C. and a wind speed of 20 m / sec to remove moisture and guided to a tenter. In the heat treatment section, the temperature is increased to 3 seconds at 140 ° C., 3 seconds at 170 ° C., and 3 seconds at 205 ° C., followed by heat treatment at 205 ° C., and 5% of lateral relaxation. A laminated biaxially stretched polyester film having a thickness of 100 μm having a coating layer b was obtained. The intrinsic viscosity of the obtained film was 0.65 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>.

In the tenter, the clip return was provided by an external return method, a clip cooling device, forced cooling by cold air at 20 ° C, and measures to prevent close contact with the clip to make the clip temperature at the TD outlet 40 ° C or less. Table 3 shows the characteristics and the evaluation results of the obtained film.

Example 2

In Example 1, except having changed into the raw material shown in Table 1 and the film forming conditions shown in Table 4, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. The stretched polyester film was obtained. The intrinsic viscosity of the obtained film was 0.66 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 6 shows the characteristics and the evaluation results of the obtained film.

Example 3

In Example 1, except having changed into the raw material shown in Table 1 and the film forming conditions shown in Table 4, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. The stretched polyester film was obtained. The intrinsic viscosity of the obtained film was 0.66 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 6 shows the characteristics and the evaluation results of the obtained film.

Example 4

In Example 1, except having changed into the raw material shown in Table 1 and the film forming conditions shown in Table 4, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. The stretched polyester film was obtained. The intrinsic viscosity of the obtained film was 0.70 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 6 shows the characteristics and the evaluation results of the obtained film.

Example 5

In Example 1, changing to the raw material shown in Table 1, adjusting the discharge amount at the time of melt extrusion, changing the thickness of an unstretched sheet, changing to the film forming conditions shown in Table 4, and having not provided an additional coating layer. A laminated biaxially stretched polyester film having a thickness of 25 μm was obtained except as in Example 1. The intrinsic viscosity of the obtained film was 0.65 dl / g. Table 6 shows the characteristics and the evaluation results of the obtained film.

Example 6

In Example 1, the same raw material as in Example 2 was used, except that the thickness of the unstretched sheet was changed by adjusting the discharge amount during melt extrusion, and changed to the film forming conditions shown in Table 4. Thus, a laminated biaxially stretched polyester film having a thickness of 50 µm having an application layer a on one side and an application layer b on the other side was obtained. The intrinsic viscosity of the obtained film was 0.64 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 6 shows the characteristics and the evaluation results of the obtained film.

Example 7

In Example 1, except having changed the raw material for B layer into the raw material shown in Table 2, it carried out similarly to Example 1, and laminated biaxial stretching of 50 micrometers in thickness which has a coating layer a on one side, and a coating layer b on the other surface. A polyester film was obtained. The intrinsic viscosity of the obtained film was 0.70 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 6 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 1

In Example 1, biaxially having a single-layer structure having a thickness of 100 µm in the same manner as in Example 1, except that the raw material shown in Table 2 and the film forming conditions shown in Table 5 were not changed and the skin layer B was not provided. The stretched polyester film was obtained. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 2

In Example 1, biaxially having a single-layer structure having a thickness of 100 µm in the same manner as in Example 1, except that the raw material shown in Table 2 and the film forming conditions shown in Table 5 were not changed and the skin layer B was not provided. The stretched polyester film was obtained. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 3

In Example 1, except having changed into the film forming conditions shown in Table 5, it carried out similarly to Example 1, and obtained the laminated biaxially stretched polyester film of thickness 100micrometer which has a coating layer a on one side, and a coating layer b on the other side. . The intrinsic viscosity of the obtained film was 0.71 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 4

Example 1 WHEREIN: Except changing the raw material for B-layer to the raw material shown in Table 3, and further changing to the film forming conditions shown in Table 5, it carried out similarly to Example 1, and apply | coated layer a to one side, and a coating layer to the other side A laminated biaxially stretched polyester film having a thickness of 100 µm having b was obtained. The intrinsic viscosity of the obtained film was 0.71 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 5

In Example 4, except having changed into the film forming conditions of Table 5, it carried out similarly to Example 4, and obtained the laminated biaxially stretched polyester film of thickness 100micrometer which has a coating layer a on one side, and a coating layer b on the other side. . The intrinsic viscosity of the obtained film was 0.71 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 6

In Example 1, except having changed into the raw material shown in Table 3, and the film forming conditions shown in Table 5, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. The stretched polyester film was obtained. The intrinsic viscosity of the obtained film was 0.70 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 7

The resin of Table 3 was prepared, it dried, and it was set as the raw material used for A layer and B layer. Subsequently, a co-extrusion melt extruder having a feed block and a T die was used to melt the raw material for layer B at 285 ° C. and the raw material for layer A at 285 ° C., respectively. Subsequently, the constitution of the layer was made B / A / B, the thickness ratio of the B layer / A layer was 0.11, and coextruded, and rapidly cooled on a cast drum to obtain an unstretched laminated sheet.

The obtained unoriented laminated sheet was sequentially biaxially stretched at 110 ° C. at 3.0 times and at 120 ° C. at 3.2 times in a longitudinal direction, and then heat-treated at 235 ° C. to obtain a laminated biaxially stretched polyester film having two kinds and three layers. . Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 8

In Example 1, except having changed into the raw material shown in Table 3, and the film forming conditions shown in Table 5, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. The stretched polyester film was obtained. The intrinsic viscosity of the obtained film was 0.70 dl / g. In addition, the final dry coating amount of the coating layer a and the coating layer b was 0.1 g / m <2>. Table 7 shows the characteristics and the evaluation results of the obtained film.

Comparative Example 9

In Example 1, except having changed the raw material shown in Table 3 and the film forming conditions shown in Table 5, it carried out similarly to Example 1, and laminated biaxially having a thickness of 100 micrometers which has a coating layer a on one side, and a coating layer b on the other surface. An attempt was made to obtain a stretched polyester film, but breakage occurred in the tenter, making it impossible to obtain a film.

The laminated polyester film for molding according to the present invention can be applied to a wide range of molding methods because of its excellent moldability at the time of heating molding, especially at low temperature and low pressure, and can be used as a molded body under normal temperature atmosphere. In addition to excellent elasticity and shape stability (heat shrinkage characteristics, thickness nonuniformity), excellent transparency, printability, solvent resistance and heat resistance, and excellent impact resistance, interior materials and exterior materials for home appliances, mobile phones, automobiles, Or there exists an advantage that it can be used suitably as a member for building materials, and the contribution to the industry is large.

Claims (8)

As a biaxially oriented laminated polyester film obtained by laminating a polyester B layer on one side or both sides of a polyester A layer, A-layer and B-layer are both copolyester or copolyester and homopolyester, and melting | fusing point (TmA: degreeC) of layer A and melting | fusing point (TmB: degreeC) of layer B are following Formula (1) And (2) at the same time, The laminated polyester film has an orientation structure in both the A layer and the B layer, the heat shrinkage at 150 ° C. is 6.0% or less in both the longitudinal direction and the width direction, and the thickness variation in the width direction is 10% or less. Polyester film.

The method of claim 1, The copolyester comprises (a) an aromatic dicarboxylic acid component, ethylene glycol and a glycol component comprising a branched aliphatic glycol or an alicyclic glycol, or (b) terephthalic acid and isophthalic acid. It consists of an aromatic dicarboxylic acid component and the glycol component containing ethylene glycol, The laminated polyester film for shaping | molding characterized by the above-mentioned. The method of claim 1, The homo-polyester is at least one member selected from the group consisting of polyethylene terephthalate, polytetramethylene terephthalate, and polybutylene terephthalate. The method of claim 1, The laminated polyester film is 10-500 micrometers in total thickness, and the thickness of B layer is 1 to 30% of the whole, The laminated polyester film for shaping | molding. The method of claim 1, The laminated polyester film is a laminated polyester film for molding, wherein the stress at 100% elongation in the longitudinal direction and the width direction of the film is 40 to 300 MPa at 25 ° C and 1 to 100 MPa at 100 ° C. The method of claim 1, The laminated polyester film is haze of 2.0% or less, The laminated polyester film for shaping | molding characterized by the above-mentioned. Process of manufacturing unstretched sheet which laminates polyester B layer on one or both sides of polyester A layer using coextrusion method, process of biaxially stretching unstretched sheet in longitudinal direction and width direction, biaxially stretched film As a manufacturing method of the laminated polyester film for shaping | molding which becomes a process of carrying out heat processing, holding | gripping with a clip, Polyester constituting the A layer and B layer is a copolyester or a mixture of copolyester and homopolyester, The heat treatment process has two or more heat treatment sections, and the maximum heating rate in the heat treatment section is 10 to 30 ° C./sec, and the maximum heat treatment temperature is (melting point of layer A-10 ° C.) to (melting point of layer A + 20 ° C.). The manufacturing method of the laminated polyester film for shaping | molding of Claim 1 characterized by the above-mentioned. The method of claim 7, wherein When transverse stretching and heat treatment are performed while retaining and retaining the film with a clip in the tenter, the vicinity of the clip is cooled using one or more of the methods (i) to (v) below, followed by the clip at the tenter outlet. A method for producing a laminated polyester film for molding, which comprises opening a film from the film. (i) How to install a heat shield on the clip (ii) adding the clip cooling mechanism to the tenter (iii) A method of sufficiently cooling the entire film by setting a long cooling section after heat setting. (iv) increase the cooling efficiency by increasing the length of the cooling section and the number of compartments; (v) Method of strengthening the cooling of the clip by using a type in which the return portion of the clip travels on the outside of the furnace.