CN105073386A

CN105073386A - Polyester film and method for producing same

Info

Publication number: CN105073386A
Application number: CN201480017885.4A
Authority: CN
Inventors: 中居真一; 浜田一范; 井上正央
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2013-03-28
Filing date: 2014-03-24
Publication date: 2015-11-18
Anticipated expiration: 2034-03-24
Also published as: TWI592284B; JP6016688B2; TW201446473A; CN105073386B; JP2014189002A; KR101591237B1; KR20150119438A; WO2014157108A1

Abstract

Provided is a polyester film that has a thickness of 100 [mu]m or less, and which satisfies formulas (I) and (II) in the film width direction, wherein, per unit distance in the film width direction, X [%/m] is the maximum value of the absolute value of a thermal shrinkage rate change amount (x) [%/m] in the direction perpendicular to the film width direction, and Y [%/m2] is the maximum value of the absolute value of a change rate (y) per unit distance of x. Further provided is a method for producing the polyester film. 0.01 < X < 2.00 (I) 0.1 <Y < 20.0 (II).

Description

Polyester film and manufacture method thereof

Technical field

The present invention relates to polyester film and manufacture method thereof.

Background technology

Polyester is applied in the various uses such as electric insulation purposes, optical applications.Wherein, as electric insulation purposes, particularly the solar cell purposes such as back-protective sheet (so-called backboard) of solar cell attracts attention in recent years.

Biaxial stretch-formed grade is carried out and the polyester film that obtains coating or paste functionality material and make functional membrane to utilize on film sometimes after melt extruding.Now, if limit roller etc. carry out transporting limit manufacture thinner polyester film, then sometimes in polyester film, gauffer, scratch etc. is produced because of a variety of causes when heating conveyance.

As the technology relevant to above-mentioned situation, disclose the aspect from size stabilization, polyester film is provided with the duplexer (for example, referring to Japanese Unexamined Patent Publication 2010-052416 publication) of the floor containing metal or metal system oxide.

In addition, the change in size of the film in heat treatment step during in order to suppress aft-loaded airfoil, disclose film and the manufacture method (for example, referring to Japanese Unexamined Patent Publication 2009-149066 publication) thereof of percent thermal shrinkage and uniformity, refractive index, the elongation at break etc. defining PETG film.

Summary of the invention

Invent problem to be solved

According to Japanese Unexamined Patent Publication 2010-052416 publication and Japanese Unexamined Patent Publication 2009-149066 publication, although show the gauffer etc. that the low thermal shrinkage of polyester film and homogenising thereof contribute to improveing polyester film, gauffer suppresses also insufficient.The thinner polyester film thickness of polyester film being reached less than 100 μm particularly cannot be suppressed to carry out the conveyance direction (MD easily produced when heating conveyance; Longitudinally, MachineDirection) wrinkle (hereinafter also referred to as " muscle shape protuberance ").In recent years, from the lightweight of product, the saving etc. of raw material that make use of film, the comparatively thinning development of film, so the gauffer of thinner polyester film suppresses to be important problem.

The present invention carries out in view of the foregoing, even if object is to provide polyester film and the manufacture method thereof of carrying out also being difficult to produce in conveyance direction when heating conveyance gauffer at thinner polyester film thickness being reached less than 100 μm, problem reaches this object.

For solving the scheme of problem

The opinion that the muscle shape protuberance that the present invention obtains thinner polyester film can be eliminated by the change of the local of the MD percent thermal shrinkage of the polyester film before reduction heating, and reach based on described opinion.

Concrete scheme for reaching above-mentioned problem is as follows.

<1> polyester film, its thickness is less than 100 μm, the maximum Y [%/m of the maximum X [%/m] of percent thermal shrinkage variable quantity x [%/m] absolute value in the direction vertical with film width of the film width per unit distance of film width and the rate of change y absolute value of the per unit distance of x ²] meet following formula (I) and (II).

0.01＜X＜2.00…(I)

0.1＜Y＜20.0…(II)

The polyester film of <2> according to <1>, wherein, the percent thermal shrinkage in the direction vertical with film width in the central portion of film width is more than 0.01% and less than 3%.

The polyester film of <3> according to <1> or <2>, wherein, the percent thermal shrinkage deviation in the direction vertical with film width of film width is more than 0.01% and less than 0.5%.

The polyester film of <4> according to any one of <1> ~ <3>, wherein, the measuring (DSC) pre-peak temperature deviation of measuring by means of differential scanning calorimetry and be more than 0.5 DEG C and less than 10 DEG C of film width.

The polyester film of <5> according to any one of <1> ~ <4>, wherein, the inherent viscosity of polyester film is more than 0.55dL/g and below 0.90dL/g.

The polyester film of <6> according to any one of <1> ~ <5>, wherein, the amount of the terminal carboxyl group of polyester film is more than 5eq/ ton and below 35eq/ ton.

The polyester film of <7> according to any one of <1> ~ <6>, wherein, from 3 officials can above polyfunctional monomer Component units be more than 0.005 % by mole and less than 2.5 % by mole containing ratio relative to whole Component units of the polyester in polyester film.

The manufacture method of a <8> polyester film, it comprises following operation: melt extruded with sheet by polyester feed stock resin, curtain coating drum on cooling and by polyester film be shaped film forming process;

Polyester film formed thereby is carried out along its length the longitudinal stretching operation of longitudinal stretching;

Polyester film is transported successively to following portion, polyester film after longitudinal stretching is carried out the cross directional stretch operation of cross directional stretch along the width vertical with length direction, wherein said each portion is: the preheating part polyester film after longitudinal stretching being preheated to the temperature that can stretch, along the width vertical with length direction, tension force is applied to the polyester film through preheating and carries out the extension section of cross directional stretch, the thermal finalization portion making its crystallization and thermal finalization is heated to the polyester film after carrying out longitudinal stretching and cross directional stretch, hot wire-CVD portion by the tension recovery of polyester film except the overstrain of striping is heated to the polyester film through thermal finalization, and by the cooling end of the polyester film cooling after hot wire-CVD,

In at least one in thermal finalization portion and hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end of the polyester film of width, and, in cooling end, the average cooling rate film width end when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to 1.01 times ~ 2 times of the average cooling rate in the central portion of film width.

The manufacture method of the polyester film of <9> according to <8>, wherein, radiation heating utilizes pottery heater processed to carry out.

The manufacture method of the polyester film of <10> according to <8> or <9>, wherein, the width L2 of the polyester film the end of the cooling end that the width L1 of the polyester film when width of the polyester film in cross directional stretch operation reaches maximum and polyester film leave from cooling end meets following formula (1), and

The conveyance speed S2 of the polyester film in the conveyance speed S1 of the polyester film in preheating part and the end of cooling end meets following formula (2).

[mathematical expression 1]

0.02 \leq \frac{L 1 - L 2}{L 1} \leq 0.15 - - - (1)

0.02 \leq \frac{S 1 - S 2}{S 1} \leq 0.15 - - - (2)

The manufacture method of the polyester film of <11> according to any one of <8> ~ <10>, wherein, cross directional stretch operation uses the biaxial stretch-formed device of the following stated, this biaxial stretch-formed device possesses preheating part, extension section, thermal finalization portion, hot wire-CVD portion, and cooling end, and use at least two holding components to hold the both ends of the width of polyester film for an end in preheating part, thus by polyester film from preheating part conveyance to cooling end,

By the holding component of an end of the width with the holding polyester film in preheating part and be adjacent to this holding component holding component interval compared with, the holding component of an end of the width of the holding polyester film in constriction cooling end and be adjacent to the interval of holding component of this holding component, thus reduce the conveyance speed of polyester film.

The manufacture method of the polyester film of <12> according to any one of <8> ~ <11>, wherein,

In cooling end, average cooling rate when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to the scope of 2 DEG C/sec ~ 100 DEG C/sec.

Invention effect

According to the present invention, even if polyester film and the manufacture method thereof of carrying out also being difficult to produce in conveyance direction when heating conveyance gauffer at thinner polyester film thickness being reached less than 100 μm can be provided.

Accompanying drawing explanation

Fig. 1 is the schematic diagram for illustration of problem of the present invention.

Fig. 2 is the schematic diagram for illustration of formula of the present invention (I) and (II).

Fig. 3 is the upper surface figure of the example representing biaxial stretcher from upper surface.

Fig. 4 is the schematic diagram of the method for the mensuration MD percent thermal shrinkage represented in embodiment.

Detailed description of the invention

< polyester film >

The thickness of polyester film of the present invention is less than 100 μm, the maximum Y [%/m of the maximum X [%/m] of percent thermal shrinkage variable quantity x [%/m] absolute value in the direction vertical with film width of the film width per unit distance on film width and the rate of change y absolute value of the per unit distance of x ²] meet following formula (I) and (II).

0.01＜X＜2.00…(I)

0.1＜Y＜20.0…(II)

Be that the film of less than 100 μm is also referred to as thinner film by thickness.

The manufacture method of polyester film describes in detail below, and thinner film is usually by using roller etc. to carry out transporting and stretching and obtain.Now, by the conveyance direction of film also referred to as MD (MachineDirection) direction.In addition, the MD direction of film is also referred to as the length direction of film.In addition, film width is the direction vertical with length direction.Film carries out on limit transporting in the film of limit manufacture by film width, also referred to as TD (laterally, TransverseDirection) direction.

In the present invention, film width is called TD or TD direction, the direction vertical with film width is called MD or MD direction.In addition, by the thermal contraction in MD direction also referred to as MD thermal contraction, its ratio is called MD percent thermal shrinkage.Therefore, the percent thermal shrinkage in vertical with film width direction is also expressed as MD percent thermal shrinkage.

In addition, the kind of polyester is not particularly limited, and the kind that can be suitable for the polyester used in the present invention describes later, particularly often uses PETG (Polyethyleneterephthalate; PET).During hereinafter referred to as PET, refer to PETG.

Polyester film is sometimes by stacked for multiple polyester film or carry out multifunction or Composite at polyester film upper strata azido functional layer.Add man-hour at such polyester film, usual lateral dominance roller etc. transports, while carry out the heating, stretching etc. of film.

If thinner polyester film is by heating conveyance, then there is polyester film in the MD direction and tighten (drawing I つれ), produce the tendency of gauffer.Be called that muscle shape swells by from the concavo-convex of the wrinkle on film in the present invention, the wrinkle on described film is film cooling under the state producing wrinkle, solidifies and remain on film.If polyester film has muscle shape protuberance, then become during applied coating solution on film and be difficult to be coated with equably.In addition, if paste the functional layers such as laminate layers on the crisp film of tool, then easily produce and enter the faults such as bubble between film and functional layer.

Thinner plastic foil such as just exists as tape all the time, but in the past, generally, uses the coating fluid using organic solvent as solvent, makes solvent distribute required temperature low (such as, less than 100 DEG C).But, in recent years, Environment Oriented protection and become tend to use water solvent (comprising the solvent of water), sometimes heat under the high temperature of about 150 DEG C to make water solvent distribute.In addition, be sometimes laminated on film by the material solidified by heating as hard coat agent or film contains hard coat agent, now, film is generally heated to 170 DEG C ~ 180 DEG C.

Therefore, in film, more easily produce wrinkle, compared with the past, the generation of muscle shape protuberance easily becomes remarkable.

Conduct in-depth research the generation of muscle shape protuberance, result is thought, muscle shape protuberance is by because of the tension force when thermal contraction produced because of heating of film and film conveyance, and film deforms with corrugated, and its immobilization produces.Knownly suppress wrinkle by the tension force etc. when suppressing film conveyance, but only like this and insufficient.

Investigated the main position produced of muscle shape protuberance in polyester film, result is known, the position that the change of MD percent thermal shrinkage is large partly in width (TD) per unit distance and the change of MD percent thermal shrinkage position are sharply concentrated and produced.

Change position real estate raw contraction in local when the heating of film sharply of the position that on width, the change of MD percent thermal shrinkage is large and MD percent thermal shrinkage is uneven, easily produces the length inequality of local.If think, the place to the length inequality producing local applies the tension force of film conveyance, then produce the inequality of stress this position (producing the place of the length inequality of local), produce the position that stress is concentrated partly.Think that easily producing muscle shape at the position that this stress is concentrated partly swells.

On the other hand, by the maximum Y [%/m of the rate of change y absolute value of the maximum X [%/m] of MD percent thermal shrinkage variable quantity x [%/m] absolute value Yu the per unit distance of x that make the every TD unit distance on the TD direction of polyester film ²] meet following formula (I) and (II), the muscle shape of polyester film can be suppressed to swell.

0.01＜X＜2.00…(I)

0.1＜Y＜20.0…(II)

The relation suppressed swelled for above-mentioned (I) and (II) and muscle shape, utilizes Fig. 1 and Fig. 2 to be described.

Fig. 1 is the schematic diagram for illustration of problem of the present invention, and Fig. 2 is the schematic diagram for illustration of formula of the present invention (I) and (II).

In Fig. 1 overlapping illustrate film the schematic diagram producing the polyester film of muscle shape protuberance by TD end along MD direction and represent the curve (D of MD shrinkage factor distribution in TD direction of position of film in TD direction of this polyester film _sh).Curve (D _sh) axle (position of the film in TD direction) on the downside of curve and the axle (MD percent thermal shrinkage) on the right side of curve be as reference axis.

The muscle shape protuberance easily produced by carrying out thinner polyester film heating conveyance easily results from the end of leaning in the TD direction of polyester film, represents in Fig. 1 with gushet.For the polyester film creating muscle shape protuberance, if along TD direction detection MD percent thermal shrinkage, then at the position MD percent thermal shrinkage substantially constant not producing muscle shape protuberance, but change sharp in the region (region of the dotted line represented with R) producing muscle shape protuberance, in the region not having muscle shape to swell, the tendency that the variable quantity that there is MD percent thermal shrinkage diminishes.

In Fig. 2, the TD direction along polyester film illustrates the position (P) of P1 ~ P6 with (such as, 0.05m interval) at equal intervals.If the MD percent thermal shrinkage at P1 place is Sh1, if the MD percent thermal shrinkage at P2 place is Sh2, until P6, measure the MD percent thermal shrinkage (Sh) at each position (P) place.

About the position of n (n is more than 1), MD percent thermal shrinkage (Shn) by position (Pn) is deducted the MD percent thermal shrinkage (Shn+1) at adjoining position (Pn+1) place, and then the amount that this value obtains divided by the distance between Pn and Pn+1 is set to the variable quantity xn of MD percent thermal shrinkage.It is " the percent thermal shrinkage variable quantity x [%/m] in the direction vertical with film width of the per unit distance of the film width of film width ".Value maximum in n xn is " the maximum X of variable quantity x ".

Such as, the MD percent thermal shrinkage (Sh1) at P1 place, position and the MD percent thermal shrinkage (Sh2) at P2 place, position are deducted and distance divided by P1 and P2 time the amount that obtains calculate as x1.Similarly, the x2 ~ x5 shown in Fig. 2 is calculated.Such as, when wherein, x4 is maximum variable quantity (x4=x _max), x4 is maximum X (x4=X).

In addition, " the rate of change y of the per unit distance of x " passes through the MD percent thermal shrinkage (Shn+1) that the MD percent thermal shrinkage (Shn) by position (Pn) is deducted adjoining position (Pn+1) place and then the amount xn this value obtained divided by the distance between Pn and Pn+1, and the MD percent thermal shrinkage (Shn+2) deducting adjoining position (Pn+2) place by the MD percent thermal shrinkage (Shn+1) of position (Pn+1) and then the difference of amount xn+1 that this value is obtained divided by the distance between Pn and Pn+1, divided by the intermediate point of Pn and Pn+1 and the intermediate point of Pn+1 and Pn+2 distance and obtain.In a y of the n-1 calculated, maximum rate of change is the maximum Y of rate of change y.

Such as, in Fig. 2, by the difference of x1 and x2 is calculated y1 divided by the distance of the intermediate point of P1 and P2 and the intermediate point of P2 and P3, by the difference of x2 and x3 is calculated y2 divided by the distance of the intermediate point of P2 and P3 and the intermediate point of P3 and P4.Calculate respectively and in the y1 ~ y4 obtained, y4 is maximum rate of change time (y4=y _max), y4 is maximum Y (y4=Y).

In Fig. 1, the region that MD percent thermal shrinkage changes sharp as already described illustrates as R.The variable quantity x calculated by the method shown in Fig. 2 is the MD shrinkage factor distribution curve (D in the region R shown in Fig. 1 _sh) the slope of tangent line Q, the maximum of the slope of the tangent line Q on TD direction is maximum X.In addition, the rate of change y calculated by the method shown in Fig. 2 is the MD shrinkage factor distribution curve (D in the region R shown in Fig. 1 _sh) the rate of change of slope, the maximum of the rate of change in TD direction is maximum Y.

By making X and Y obtained like this meet 0.01 < X < 2.00 (formula (I)) in the present invention, and, 0.1 < Y < 20.0 (formula (II)), thus the change suppressing the local of the MD percent thermal shrinkage of the reason of the muscle shape protuberance becoming polyester film.Diminished by the variable quantity reducing X and Y, MD percent thermal shrinkage, the percent thermal shrinkage as polyester film entirety easily becomes even.But although mechanism unclear, even if percent thermal shrinkage deviation diminishes also easily produce muscle shape protuberance, X and Y all specifies lower limit.

Below, polyester film of the present invention and manufacture method thereof are described in detail.

In addition, in the present invention, the film surface temperature of the film that heating conveyance refers in the conveyance of polyester film is heated to more than 130 DEG C, and the present invention reaches when the heating of more than 200 DEG C at higher temperature transports at the film surface temperature of film and also can be suitable for.

(formula (I) and (II))

In the present invention, the maximum X [%/m] of MD percent thermal shrinkage variable quantity x [%/m] absolute value of the every TD unit distance on the width (TD) of polyester film meets 0.01 < X < 2.00 (formula (I)).

If X is less than 0.01, although then mechanism is unclear, film becomes on the whole and easily produces muscle shape protuberance.If X is more than 2, then the position of concentrating partly at stress becomes and easily produces muscle shape protuberance.

X is 0.05 < X < 1.50 preferably, more preferably 0.10 < X < 1.00.

In the present invention, the maximum Y [%/m of the rate of change y absolute value of the per unit distance of x ²] meet 0.1 < Y < 20.0 (formula (II)).If Y is lower than 0.1, although then mechanism is unclear, film becomes on the whole and easily produces muscle shape protuberance.If Y is more than 20, then the position of concentrating partly at stress becomes and easily produces muscle shape protuberance.

Y is 0.5 < Y < 15 preferably, more preferably 1 < Y < 10.

As already described, muscle shape protuberance easily produces when thinner polyester film being carried out heating conveyance, in the present invention, is that the polyester film of less than 100 μm is as object using thickness.The polyester film of thickness more than 100 μm is difficult to produce muscle shape protuberance.The thickness of polyester film is thin, easily obtains effect of the present invention, and the thickness of polyester film is preferably more than 5 μm and less than 75 μm, is more preferably more than 10 μm and less than 63 μm.

From the view point of suppressing further muscle shape protuberance, the MD percent thermal shrinkage in the central portion of the width (TD direction) of polyester film is preferably more than 0.01% and less than 3%.Wherein, when the central portion of polyester film width refers to the position at an end in the TD direction of setting polyester film and the center of another end as C, centered by C, reach respectively in TD direction and MD direction the total length in the TD direction of polyester film ± region of 10%.

By the MD percent thermal shrinkage in the TD direction central portion of polyester film is set to more than 0.01%, be difficult to produce basic relaxing in the heating conveyance of polyester film, the generation of the muscle shape protuberance easily produced in lax part can be suppressed.By the MD percent thermal shrinkage in the central portion of TD direction is set to less than 3%, the muscle shape protuberance produced because of thermal contraction can be suppressed.

MD percent thermal shrinkage in the TD direction central portion of polyester film is more preferably more than 0.05% and less than 2%, and more preferably more than 0.10% and less than 1.5%.

In addition, from the view point of suppressing further muscle shape protuberance, the MD percent thermal shrinkage deviation on the TD direction of polyester film is preferably more than 0.01% and less than 0.5%.

Wherein, the MD percent thermal shrinkage deviation on so-called TD direction, refers to the difference of the maxima and minima of MD percent thermal shrinkage when measuring the MD percent thermal shrinkage Sh at P place, n position as shown in Figure 2.

Such as, the diaphragm of 11 position P1 ~ P11 that the TD direction of polyester film is arranged at equal intervals is sampled.Measure each MD percent thermal shrinkage Sh1 ~ Sh11 of the diaphragm at P1 ~ P11 place, as long as using the difference of the maxima and minima in Sh1 ~ Sh11 as the MD percent thermal shrinkage deviation on TD direction.Below, by " the MD percent thermal shrinkage deviation on TD direction " also referred to as Δ Sh.

By making the MD percent thermal shrinkage deviation (Δ Sh) on the TD direction of polyester film be more than 0.01%, although mechanism is unclear, film becomes on the whole and is difficult to produce muscle shape protuberance.By making Δ Sh be less than 0.5%, becoming and easily meeting formula (I) and formula (II), the generation that muscle shape swells can be suppressed further.

Δ Sh is more preferably less than 4%, and more preferably less than 0.3%.

Polyester film, by measuring (DSC) pre-peak temperature deviation of measuring by means of differential scanning calorimetry and be set to more than 0.5 DEG C and less than 10 DEG C further by TD direction, can further suppress muscle shape to swell.

Wherein, so-called DSC is that means of differential scanning calorimetry measures (Differentialscanningcalorimetry), and " the pre-peak temperature " of so-called DSC refers to the temperature at the peak occurred at first when carrying out DSC to polyester film and measuring.

The pre-peak temperature of DSC be generally equivalent to polyester film biaxial stretch-formed in thermal finalization in the cross directional stretch operation of carrying out time being up to of polyester film reach film surface temperature (heat setting temperature).

In addition, the pre-peak temperature of DSC measures at means of differential scanning calorimetry the value obtained by conventional method in (DSC).

In addition, pre-peak temperature deviation is obtained in the same manner as MD percent thermal shrinkage deviation (Δ Sh).That is, the diaphragm of 11 position P1 ~ P11 that the TD direction of polyester film is arranged at equal intervals is sampled.DSC mensuration is carried out to the diaphragm at P1 ~ P11 place, measures each pre-peak temperature Tpp1 ~ Tpp11, the difference of the maxima and minima in Tpp1 ~ Tpp11 is set to the pre-peak temperature deviation of the DSC in TD direction.Below, by " the pre-peak temperature deviation of the DSC in TD direction " also referred to as Δ Tpp.

If the TD direction MD percent thermal shrinkage of polyester film becomes too even, then film becomes on the whole and easily produces muscle shape protuberance.

By making the pre-peak temperature deviation (Δ Tpp) of the DSC in the TD direction of polyester film be more than 0.5 DEG C, the muscle shape protuberance easily produced in film entirety can be suppressed.

By making Δ Tpp be less than 10 DEG C, becoming and easily meeting formula (I) and formula (II), the generation that muscle shape swells can be suppressed further.

Δ Tpp is more preferably more than 0.5 DEG C and less than 7 DEG C, further preferably more than 0.5 DEG C and less than 5 DEG C, most preferably is more than 0.5 DEG C and less than 4 DEG C.

Weatherability is improved, the inherent viscosity (IV of polyester film from the view point of the hydrolytic resistance improving polyester film; IntrinsicViscosity) more than 0.55dL/g and below 0.90dL/g is preferably, be more preferably more than 0.60dL/g and below 0.80dL/g, more preferably more than 0.62dL/g and below 0.78dL/g, most preferably is more than 0.63dL/g and below 0.75dL/g.

(end COOH measures (also referred to as acid number), AV to the amount of the terminal carboxyl group of polyester film; AcidValue) preferably more than 5eq/ ton and below 35eq/ ton.End COOH amount is more preferably more than 6eq/ ton and below 30eq/ ton, more preferably more than 7eq/ ton and below 28eq/ ton.

In addition, in this description, " eq/ ton " represents the molar equivalent of every 1 ton.

Polyester is dissolved into benzyl alcohol/chloroform (=2/3 by AV completely; Volume ratio) mixed solution in, use phenol red as indicator, carry out titration, the value calculated by its titer with titer (0.025NKOH-methyl alcohol mixed solution).

Polyester film makes dicarboxylic acid component and diol component copolymerization and the material synthesized.About the details of dicarboxylic acid component and diol component, describe later.In addition, the polyester film of the present invention total (a+b) preferably comprised from the number (a) of carboxyl and the number (b) of hydroxyl is that the polyfunctional monomer of more than 3 is (hereinafter also referred to as " 3 officials can polyfunctional monomer " above or referred to as " polyfunctional monomer ".) the polyester film of Component units.

Polyester film of the present invention can obtain by such as making (A) dicarboxylic acid component and (B) diol component carry out esterification and/or ester exchange reaction by known method as will be described later, and more preferably copolymerization thereon 3 official can above polyfunctional monomer and obtaining.About details such as the illustration of dicarboxylic acid component, diol component and polyfunctional monomer etc., preferred modes, as will be described later.

~ from polyfunctional monomer Component units ~

As the Component units that the total (a+b) from the number (a) of carboxyl and the number (b) of hydroxyl is the polyfunctional monomer of more than 3, as will be described later, the carboxylic acid that the number (a) that can list carboxyl is more than 3 and the polyfunctional monomer that the hydroxyl value (b) such as their ester derivant or acid anhydrides is more than 3 and " there is in a part both hydroxyl and carboxyl and the number (a) of carboxyl and the total (a+b) of the number (b) of hydroxyl are the hydroxyl acids of more than 3 " etc.About details such as their illustration and preferred modes, as will be described later.

In addition, at the carboxyl terminal of carboxylic acid or the hydroxyl acids such as carboxyl terminal addition l-lactide, d-lactide, hydroxybenzoic acid of " there is in a part the polyfunctional monomer of both hydroxyl and carboxyl " and derivative, the multiple materials be formed by connecting of this hydroxyl acids etc. and the compound obtained also be applicable to.

They can be used alone one, as required, and also can by multiple and use.

In polyester film of the present invention, from 3 officials can above polyfunctional monomer Component units be preferably more than 0.005 % by mole and less than 2.5 % by mole containing ratio relative to whole Component units of the polyester in polyester film.The ratio that contains from the Component units of polyfunctional monomer is more preferably more than 0.020 % by mole and less than 1 % by mole, more preferably more than 0.025 % by mole and less than 1 % by mole, more preferably more than 0.035 % by mole and less than 0.5 % by mole, be particularly preferably more than 0.05 % by mole and less than 0.5 % by mole, most preferably be more than 0.1 % by mole and less than 0.25 % by mole.

Can the Component units of above polyfunctional monomer from 3 officials by making to exist in polyester film, can obtain the Component units of above polyfunctional monomer branching out the structure of polyester molecule chain by from 3 officials, the mutual winding between polyester molecule can be promoted.Consequently, even if cause polyester molecule to occur to be hydrolyzed and molecular weight reduction under being exposed to hot and humid environment, being mutually wound around by being formed between polyester molecule, also can suppressing the embrittlement of polyester film, more excellent weatherability can be obtained.And then so mutual winding is also effective for the suppression of thermal contraction.Infer this is because, the motility of polyester molecule reduces by the mutual winding of above-mentioned polyester molecule, even if so molecule is wanted because of heat to shrink also cannot shrink, the thermal contraction of polyester film is inhibited.

In addition, by comprise 3 officials can above polyfunctional monomer as Component units, composition in the coating layer not having the functional group that uses and coating to be formed on polyester film in polycondensation after esterification produces hydrogen bond, covalent bond, thus the adhesiveness of coating layer and polyester film is kept more well, the generation of peeling off effectively can be prevented.The polyester film used in backboard used for solar batteries adheres to the sealant such as EVA after coating forms the coating layer such as easy adhesive layer, even to be positioned over outside room etc. when being exposed under environment such in wind and rain for a long time, the good adhesiveness being difficult to peel off also can be obtained.

Therefore, by make from 3 officials can above polyfunctional monomer Component units be more than 0.005 % by mole containing ratio, weatherability, low thermal shrinkage behavior and the adhesion of coating layer be formed on polyester film with coating easily improve further.In addition, by make from 3 officials can above polyfunctional monomer Component units be less than 2.5 % by mole containing ratio, due to from 3 officials can the Component units volume of above polyfunctional monomer large, be difficult to form crystallization so can suppress to become.Consequently, the formation of the low mobile composition formed via crystallization can be promoted, suppress water-disintegrable reduction.And then by can the large volume of Component units of above polyfunctional monomer from 3 officials, the micro concavo-convex amount on film surface increases, so easily embody Anchoring Effect, polyester film improves with the adhesion of the coating layer that coating is formed on this film.In addition, by this large volume, the free volume (intermolecular gap) of increase is inhibited, and can suppress because polyester molecule skids off (すり order け Ru in large free volume) and the thermal contraction produced.In addition, with from 3 officials can the interpolation of Component units of above polyfunctional monomer excessive and the reduction of glass transition temperature (Tg) that is that produce also is inhibited, be also effective for preventing the reduction of weatherability.

~ from end-capping reagent structure division ~

Polyester film of the present invention preferably also has the structure division of free end-capping reagent in oxazoline based compound, carbon imide compound and epoxide.In addition, " structure division from end-capping reagent " refers to the carboxylic acid reaction of end-capping reagent and polyester end and is bonded in the structure of end.

If end-capping reagent is contained in polyester film, then due to the carboxylic acid reaction of end-capping reagent and polyester end, is bonded in polyester end and exists, easily end COOH being measured (AV value) stably maintain value desired by already described preferred scope etc. so become.That is, be inhibited by the poly-ester hydrolysis that terminal carboxylic promotes, weatherability can be kept higher.In addition, due to the end section being bonded in polyester end and strand, to become volume large, and the micro concavo-convex amount on film surface increases, and easily embodies Anchoring Effect so become, and polyester film improves with the adhesion of the coating layer that coating is formed on this film.And then end-capping reagent volume is large, and polyester molecule can be suppressed in free volume to skid off movement.Consequently, also there is the effect of the thermal contraction of the movement suppressed with molecule.

In addition, end-capping reagent makes with the carboxyl reaction of the end of polyester the additive that the carboxyl terminal amount of polyester reduces.

End-capping reagent can be used alone a kind, also two or more can be combinationally used.

End-capping reagent relative to polyester film quality preferably with more than 0.1 quality % and the scope of below 5 quality % contain, be more preferably more than 0.3 quality % and below 4 quality %, more preferably more than 0.5 quality % and below 2 quality %.

Be more than 0.1 quality % by what make the end-capping reagent in polyester film containing ratio, become good with the adhesion of coating layer, can reach simultaneously and reduce by AV the weatherability that effect brings and improve, and can low thermal shrinkage behavior be given.In addition, if the end-capping reagent in polyester film is below 5 quality % containing ratio, then become good with the adhesion of coating layer, the reduction of the glass transition temperature (Tg) of the polyester simultaneously produced because of the interpolation of end-capping reagent is inhibited, and can suppress the reduction of the weatherability caused thus, the increase of thermal contraction.This is because, the reactivity of the relatively polyester because Tg reduces can be suppressed to increase and the water-disintegrable increase that produces, the motility of the polyester molecule increased because Tg reduces can be suppressed to become easy increase and the thermal contraction that produces.

As the end-capping reagent in the present invention, preferably there is the compound of carbon imidodicarbonic diamide base, epoxy radicals, Huo oxazolinyl.As the object lesson of end-capping reagent, can be suitable for listing carbon imide compound, epoxide, oxazoline based compound etc.

The carbon imide compound with carbon imidodicarbonic diamide base has 1 functionality carbon imidodicarbonic diamide and multi-functional carbon imidodicarbonic diamide.As 1 functionality carbon imidodicarbonic diamide, such as dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethyl carbon imidodicarbonic diamide, diisobutyl carbon imidodicarbonic diamide, dioctyl carbon imidodicarbonic diamide, ter /-butylisopropyl carbon imidodicarbonic diamide, diphenyl carbon imidodicarbonic diamide, two-tert-butyl group carbon imidodicarbonic diamide and two-betanaphthyl carbon imidodicarbonic diamide etc. can be listed, be preferably dicyclohexylcarbodiimide, diisopropylcarbodiimide.

In addition, as multi-functional carbon imidodicarbonic diamide, preferred degree of polymerization is the poly-carbon imidodicarbonic diamide of 3 ~ 15.Poly-carbon imidodicarbonic diamide generally has the repetitive represented with "-R-N=C=N-" etc., and R represents the concatenating group of the divalent such as alkylidene, arlydene.As such repetitive, such as 1 can be listed, 5-naphthalene carbon imidodicarbonic diamide, 4, 4 '-diphenyl methane carbon imidodicarbonic diamide, 4, 4 '-diphenyldimethyhnethane carbon imidodicarbonic diamide, 1, 3-phenylene carbon imidodicarbonic diamide, 2, 4-toluene support carbon imidodicarbonic diamide, 2, 6-toluene support carbon imidodicarbonic diamide, 2, 4-toluene support carbon imidodicarbonic diamide and 2, the mixture of 6-toluene support carbon imidodicarbonic diamide, hexa-methylene carbon imidodicarbonic diamide, cyclohexane-1, 4-carbon imidodicarbonic diamide, xyxylene carbon imidodicarbonic diamide, isophorone carbon imidodicarbonic diamide, dicyclohexyl methyl hydride-4, 4 '-carbon imidodicarbonic diamide, hexahydrotoluene carbon imidodicarbonic diamide, durol dimethyl carbon imidodicarbonic diamide, 2, 6-diisopropyl phenyl carbon imidodicarbonic diamide and 1, 3, 5-triisopropylbenzene-2, 4-carbon imidodicarbonic diamide etc.

From the viewpoint of the generation of isocyanate-based gas suppressing to cause because of thermal decomposition, the carbon imide compound that the preferred heat resistance of carbon imide compound is high.In order to improve heat resistance, molecular weight (degree of polymerization) is more high more preferred, more preferably the end of carbon imide compound is made the high structure of heat resistance.In addition, by reducing the temperature being carried out by polyester feed stock resin melt extruding, the raising effect of the weatherability brought by carbon imide compound and the reduction effect of thermal contraction can more effectively be obtained.

The generation of the isocyanate-based gas when polyester film employing carbon imide compound keeps 30 minutes at temperature 300 DEG C is preferably 0 quality % ~ 0.02 quality %.If the generation of isocyanate-based gas is below 0.02 quality %, then becomes in polyester film and be difficult to generate bubble (space), therefore, be difficult to form the concentrated position of stress, so destruction, the stripping of easily generation in polyester film can be prevented.Thus, the adhesion and between adjacent material becomes good.

Wherein, isocyanate-based gas is the gas with NCO, such as diisopropyl benzene based isocyanate, 1 can be listed, 3,5-triisopropyl phenyl diisocyanate, 2-amino-1,3,5-triisopropyl phenyl-6-isocyanates, HMDI, IPDI and cyclohexyl isocyanate etc.

As the epoxide with epoxy radicals, as preferred example, epihydric alcohol ester compound, glycidyl ether compound etc. can be listed.

As the object lesson of epihydric alcohol ester compound, glycidyl benzoate can be listed, p t butylbenzoic acid ethylene oxidic ester, to toluic acid ethylene oxidic ester, cyclohexane-carboxylic acid ethylene oxidic ester, n-nonanoic acid ethylene oxidic ester, stearic acid ethylene oxidic ester, laurate ethylene oxidic ester, palmitic acid ethylene oxidic ester, behenic acid ethylene oxidic ester, neodecanoic acid (versaticacid) ethylene oxidic ester, oleic acid ethylene oxidic ester, linoleic acid ethylene oxidic ester, leukotrienes ethylene oxidic ester, Shan Yu acetylenic acid ethylene oxidic ester, stearolic acid ethylene oxidic ester, terephthalic acid diglycidyl ester, Diglycidyl M-phthalate, o-phthalic acid diglycidyl ester, naphthalene dicarboxylic acids 2-glycidyl ester, methylterephthalic acid's 2-glycidyl ester, hexahydrophthalic acid 2-glycidyl ester, tetrahydrophthalic acid 2-glycidyl ester, cyclohexane dicarboxylic acid 2-glycidyl ester, adipic acid 2-glycidyl ester, butanedioic acid 2-glycidyl ester, Diglycidyl Sebacate, dodecanedioic acid 2-glycidyl ester, octadecane dicarboxylic acids 2-glycidyl ester, trimellitic acid three-glycidyl ester and Pyromellitic Acid tetra glycidyl ester etc.

In addition, as the object lesson of glycidyl ether compound, phenyl glycidyl ether can be listed, O-phenyl glycidyl ether, 1, two (the β of 4-, γ-glycidoxy) butane, 1, two (the β of 6-, γ-glycidoxy) hexane, 1, two (the β of 4-, γ-glycidoxy) benzene, 1-(β, γ-glycidoxy)-2-Ethoxyethane, 1-(β, γ-glycidoxy)-2-benzyloxy ethane, 2, 2-pair-[p-(β, γ-glycidoxy) phenyl] propane and 2, 2-pair-(4-hydroxy phenyl) propane or 2, 2-is two-the bisglycidyl polyethers etc. that obtained by the reaction of bis-phenol and epoxychloropropane such as (4-hydroxy phenyl) methane.

Zuo is oxazoline compound, can from the compound of Ju You oxazolinyl suitable choice for use, wherein preferred bisoxazoline compounds.

As bisoxazoline compounds, such as 2 can be exemplified, 2 '-bis-(2-oxazoline), 2,2 '-bis-(4-methyl-2-oxazoline), 2,2 '-bis-(4,4-dimethyl-2-oxazoline), 2,2 '-bis-(4-ethyl-2-oxazoline), 2,2 '-bis-(4,4 '-diethyl-2-oxazoline), 2,2 '-bis-(4-propyl group-2-oxazoline), 2,2 '-bis-(4-butyl-2-oxazoline), 2,2 '-bis-(4-hexyl-2-oxazoline), 2,2 '-bis-(4-phenyl-2-oxazoline), 2,2 '-bis-(4-cyclohexyl-2-oxazoline), 2,2 '-bis-(4-benzyl-2-oxazoline), 2,2 '-TOPOT 2,2′ p phenylenebis (2-oxazoline), 2,2 '-metaphenylene two (2-oxazoline), 2,2 '-adjacent phenylene two (2-oxazoline), 2,2 '-TOPOT 2,2′ p phenylenebis (4-methyl-2-oxazoline), 2,2 '-TOPOT 2,2′ p phenylenebis (4,4-dimethyl-2-oxazoline), 2,2 '-metaphenylene two (4-methyl-2-oxazoline), 2,2 '-metaphenylene two (4,4-dimethyl-2-oxazoline), 2,2 '-ethylenebis (2-oxazoline), 2,2 '-tetramethylene two (2-oxazoline), 2,2 '-hexa-methylene two (2-oxazoline), 2,2 '-eight di-2-ethylhexylphosphine oxide (2-oxazoline), 2,2 '-decamethylene two (2-oxazoline), 2,2 '-ethylenebis (4-methyl-2-oxazoline), 2,2 '-tetramethylene two (4,4-dimethyl-2-oxazoline), 2,2 '-9,9 '-biphenoxyl ethane two (2-oxazoline), 2,2 '-cyclohexylidene two (2-oxazoline) and 2,2 '-diphenylene two (2-oxazoline) etc.In them, from the view point of with the reactivity of polyester is good and the raising effect of weatherability is high, most preferably 2,2 '-bis-(2-oxazoline).

Bisoxazoline compounds only otherwise damage effect of the present invention, can be used alone a kind, also two or more can be combinationally used.

In the present invention, above-mentioned or 3 officials described later above polyfunctional monomer, end-capping reagent individually can use one, also can by they two kinds combinationally use.

As long as it is that the method for the polyester film of less than 100 μm then can be made by arbitrary method that polyester film of the present invention can manufacture the thickness meeting formula (I) and (II).In the present invention, optimally can be made by the manufacture method of polyester film of the present invention such as shown below.

Below, the manufacture method of polyester film of the present invention is specifically described.

The manufacture method > of < polyester film

The manufacture method of polyester film of the present invention comprises following operation:

Polyester feed stock resin is melt extruded with sheet, curtain coating drum on cooling and by polyester film be shaped film forming process;

In at least one in thermal finalization portion and hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end of the polyester film of width, and, in cooling end, the average cooling rate film width end when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to the method for 1.01 times ~ 2 times of the average cooling rate in the central portion of film width.

The manufacture method of polyester film of the present invention can also comprise other operation.

The manufacture method of polyester film of the present invention roughly comprises film forming process, longitudinal stretching operation and cross directional stretch operation.Longitudinal stretching refers to the stretching to length direction (MD direction) of polyester film, and cross directional stretch refers to the stretching to width (TD direction) of polyester film.

Cross directional stretch operation is divided into preheating part, extension section, thermal finalization portion, hot wire-CVD portion and cooling end, by polyester film conveyance to each portion.

And then, in the manufacture method of polyester film of the present invention, in both the thermal finalization portion in cross directional stretch operation or hot wire-CVD portion or thermal finalization portion and hot wire-CVD portion, utilize heater to carry out selective radiation heating to the end, TD direction of polyester film.

By making the manufacture method of polyester film, there is above-mentioned formation, the thickness that easy manufacture meets already described formula (I) and (II) is the polyester film of less than 100 μm, even if easily manufacture at the polyester film carrying out also being difficult to when heating conveyance the gauffer (muscle shape protuberance) producing MD direction.

As already described, in the manufacture method of polyester film in the past, also suppress gauffer, attempt size stabilization, but cannot manufacture thinner as the present invention and meet the polyester of formula (I) and (II).

Such as in Japanese Unexamined Patent Publication 2009-149066 publication, think due to 1 below) and 2) shown in reason, so the polyester film meeting formula (I) and (II) cannot be manufactured.

1) the MD percent thermal shrinkage change of film end periphery

The MD percent thermal shrinkage of polyester film is generally determined by the relax level of the crystallization degree of polyester and the polyester molecule in MD direction that form film., there is the tendency that MD percent thermal shrinkage becomes lower in the crystallization degree of polyester and the relax level of polyester molecule more progress.

Usually, when utilizing the stretching devices such as biaxial stretch-formed device to carry out the PET of cross directional stretch, the crystallization degree of PET and the relax level of PET molecule are determined by the temperature in the thermal finalization portion of stretching device.The heat setting temperature of film is higher, and the crystallization degree MD percent thermal shrinkage that is higher, polyester film that there is polyester becomes lower tendency.

When utilizing stretching device to carry out cross directional stretch and thermal finalization, film clip etc. is held component hold, but this holding component often reaches the temperature of about 100 DEG C ~ about 150 DEG C through outlet (when polyester film leaves from cooling end) from the entrance of stretching device (when polyester film enters preheating part).The heat setting temperature of film reaches 200 DEG C of front and back in the case of pet usually, but lower than heat setting temperature owing to holding the temperature of component self, so thermal runaway is to holding member side, and the easy step-down of heat setting temperature of inevitable mulch film end side.Therefore, the MD percent thermal shrinkage of film also easily forms the distribution that film end becomes such greatly.Therefore, think and produce the position that changes, the anxious high ground of MD percent thermal shrinkage in film end periphery, become muscle shape protuberance when easily producing heating conveyance at this position.

2) the trickle variation of MD percent thermal shrinkage

Think that the MD percent thermal shrinkage of polyester film is also one of reason of the generation that muscle shape cannot be suppressed to swell with the situation of trickle spacing change.

Even if the variation self of polyester film MD percent thermal shrinkage is little, if the spacing of variation is trickle, then because " rate of change of per unit distance " of MD percent thermal shrinkage becomes large, so sometimes also become the main cause of muscle shape protuberance generation.The mechanism that the variation of this trickle spacing is detailed is also unclear, but thinks that film is by chilling in the cooling end of stretching device, in face, thus produces trickle residual stress uneven, causes therefrom.

Compared with thin polyester film because thermal capacity is little, so become the direction of chilling in the cooling end of stretching device inevitably, easily produce trickle MD percent thermal shrinkage as described above variation.Sometimes therefore the reason heating muscle shape when transporting and swell is become.

With regard to polyester film in the past, think due to for above-mentioned 1) and 2) countermeasure insufficient, so produce muscle shape protuberance in film.

On the other hand, according to the manufacture method of polyester film of the present invention, in at least one in thermal finalization portion and hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end of the polyester film of width (TD direction), and, in cooling end, the average cooling rate in the end, TD direction of film is set to 1.01 times ~ 2 times of the average cooling rate in the central portion in film TD direction.

Therefore, it is possible to avoid the cooling of the end, film TD direction of the holding component via stretching device, result from the chilling of film of thickness of film.Particularly by making the average cooling rate of the film end in cooling end larger than the average cooling rate of film central portion, the trickle variation of the MD percent thermal shrinkage of film can be reduced.

Consequently, the thinner polyester film made by the manufacture method of polyester film of the present invention meets already described formula (I) and (II).

Below, with regard to the details of the manufacture method of polyester film of the present invention, for each operation of film forming process, longitudinal stretching operation and cross directional stretch operation, be described in detail respectively.

(film forming process)

In film forming process, polyester feed stock resin is melt extruded with sheet, curtain coating drum cools and polyester film is shaped.

About the method that polyester feed stock resin is carried out melt extruding and polyester feed stock resin, be not particularly limited, but the catalyst, polymerization etc. by using in the synthesis of polyester feed stock resin, the inherent viscosity that inherent viscosity reaches desired can be made.

First, polyester feed stock resin is described.

(polyester feed stock resin)

As long as polyester feed stock resin becomes the raw material of polyester film and comprises the material of polyester, be then not particularly limited, except polyester, the slurry of inorganic particulate or organic filler can also be comprised.In addition, polyester feed stock resin can also comprise the titanium elements from catalyst.

The kind of the polyester comprised in polyester feed stock resin is not particularly limited.

Dicarboxylic acid component and diol component can be utilized to synthesize, also can use commercially available polyester.

When synthesizing polyester, can obtain by making such as (A) dicarboxylic acid component and (B) diol component utilize known method to carry out esterification and/or ester exchange reaction.

As (A) dicarboxylic acid component, such as malonic acid can be listed, butanedioic acid, glutaric acid, adipic acid, suberic acid, decanedioic acid, dodecanedioic acid, dimer acid, eicosane diacid, pimelic acid, azelaic acid, methylmalonic acid, the aliphatic dicarboxylic acid classes such as ethyl malonic acid, adamantane dicarboxylic acids, norbornene dicarboxylic acids, isobide, cyclohexane dicarboxylic acid, the alicyclic dicarboxylic acids such as naphthalane dicarboxylic acids, terephthalic acid (TPA), M-phthalic acid, phthalic acid, 1, 4-naphthalene dicarboxylic acids, 1, 5-naphthalene dicarboxylic acids, 2, 6-naphthalene dicarboxylic acids, 1, 8-naphthalene dicarboxylic acids, 4, 4 '-diphenyldicarboxylic acid, 4, 4 '-diphenyl ether dicarboxylic acids, 5-sodium sulfo isophthalate, phenyl indane dicarboxylic acid, anthracene dicarboxylic acids, luxuriant and rich with fragrance dicarboxylic acids, 9, the dicarboxylic acids such as aromatic dicarboxylic acid or its ester derivants such as 9 '-bis-(4-carboxyl phenyl) fluorenic acid.

As (B) diol component, such as ethylene glycol, 1 can be listed, 2-propane diols, 1, ammediol, Isosorbide-5-Nitrae-butanediol, 1,2-butanediol, 1, ester ring type glycols, the bisphenol-As, 1 such as the aliphatic diol classes such as 3-butanediol, cyclohexanedimethanol, spiral shell glycol, isobide, 3-benzene dimethanol, Isosorbide-5-Nitrae-benzene dimethanol, 9, the diol compounds such as aromatic diol class such as 9 '-bis-(4-hydroxy phenyl) fluorenes.

As (A) dicarboxylic acid component, preferably use the situation of at least a kind of aromatic dicarboxylic acid.More preferably in dicarboxylic acid component, aromatic dicarboxylic acid is contained as main component.Also can containing the dicarboxylic acid component beyond aromatic dicarboxylic acid.As such dicarboxylic acid component, it is the ester derivant etc. of aromatic dicarboxylic acid etc.

In addition, so-called " main component " refers to that the ratio shared in dicarboxylic acid component of aromatic dicarboxylic acid is more than 80 quality %.

In addition, as (B) diol component, the situation of at least a kind of aliphatic diol is preferably used.As aliphatic diol, can ethylene glycol be comprised, preferably contain ethylene glycol as main component.

In addition, so-called main component refers to that the ratio shared in diol component of ethylene glycol is more than 80 quality %.

The use amount of diol component (such as ethylene glycol), relative to dicarboxylic acid component's (particularly aromatic dicarboxylic acid (such as terephthalic acid (TPA))) and 1 mole of its ester derivant used as required, is preferably the scope of 1.015 ~ 1.50 moles.This use amount is more preferably the scope of 1.02 ~ 1.30 moles, more preferably the scope of 1.025 ~ 1.10 moles.If the scope of this use amount more than 1.015 moles, then esterification is carried out well, if the scope of less than 1.50 moles, the pair of the diethylene glycol such as caused by the dimerization of ethylene glycol then can be suppressed to generate, the numerous characteristics such as fusing point or glass transition temperature, crystallinity, heat resistance, hydrolytic resistance, weatherability can be kept well.

The total (a+b) that polyester feed stock resin in the present invention preferably wraps the number (b) of carboxylic number (a) and hydroxyl is that the polyfunctional monomer of more than 3 is as copolymer composition (3 officials can constituent) above." comprise polyfunctional monomer as copolymer composition (3 officials can constituent) above " and mean the Component units comprised from polyfunctional monomer.

As the Component units that the total (a+b) from the number (a) of carboxyl and the number (b) of hydroxyl is the polyfunctional monomer of more than 3, the Component units from carboxylic acid shown below can be listed.

Number (a) as carboxyl is the example of the carboxylic acid (polyfunctional monomer) of more than 3, as the aromatic carboxylic acid of 3 officials' energy, can list such as trimesic acid, trimellitic acid, Pyromellitic Acid, naphthalene tricarboxylic acids, anthracene tricarboxylic acids etc., as the aliphatic carboxylic acid of 3 officials' energy, can list such as methane tricarboxylic acids, ethane tricarboxylic acids, tricarballylic acid, butane tricarboxylic acid etc., as the aromatic carboxylic acid of 4 officials' energy, can list such as benzene tertacarbonic acid, benzophenone tetrabasic carboxylic acid, naphthalene tetracarboxylic acid, anthracene tetrabasic carboxylic acid, perylene tetracarboxylic acids etc., as the aliphatic carboxylic acid of 4 officials' energy, can list such as ethane tetrabasic carboxylic acid, ethylidene tetrabasic carboxylic acid, BTCA, pentamethylene tetrabasic carboxylic acid, cyclopentanetetracarboxylic, adamantane tetrabasic carboxylic acids etc., can above aromatic carboxylic acid as 5 officials, can list such as benzene pentacarbonic acid, benzene hexacarboxylic acid, naphthalene pentacarboxylic acid, naphthalene hexacarboxylic acid, naphthalene seven carboxylic acid, naphthalene eight carboxylic acid, anthracene pentacarboxylic acid, anthracene hexacarboxylic acid, anthracene seven carboxylic acid, anthracene eight carboxylic acids etc., can above aliphatic carboxylic acid as 5 officials, can list such as ethane pentacarboxylic acid, ethane seven carboxylic acid, butane pentacarboxylic acid, butane seven carboxylic acid, pentamethylene pentacarboxylic acid, cyclohexane pentacarboxylic acid, cyclohexane hexacarboxylic acid, adamantane pentacarboxylic acid, adamantane hexacarboxylic acid etc.

In the present invention, their ester derivant, acid anhydrides etc. can be listed as an example, but be not limited to these.

In addition, also suitable be used in above-mentioned carboxylic acid the hydroxyl acids such as carboxyl terminal addition l-lactide, d-lactide, hydroxybenzoic acid and derivative, the multiple materials be formed by connecting of this hydroxyl acids etc. and the compound that obtains.

They can be used alone a kind, as required, and also can by multiple and use.

It is the example of the polyfunctional monomer of more than 3 as hydroxyl value (b), as the aromatic compound of 3 officials' energy, such as trihydroxy benzene, trihydroxynaphthalene, trihydroxy anthracene, trihydroxy chalcone, trihydroxyflavone, trihydroxy cumarin can be listed, as the aliphatic alcohol of 3 officials' energy, such as glycerine, trimethylolpropane, propane triol can be listed, as the aliphatic alcohol of 4 officials' energy, such as pentaerythrite etc. can be listed.In addition, the C-terminal addition glycols of above-mentioned compound is also preferably used in and the compound obtained.

They can be used alone a kind, as required, and also can by multiple and use.

In addition, as other polyfunctional monomers other than the above, also can list in a part there is both hydroxyl and carboxyl and the total (a+b) of the number (b) of the number (a) of carboxyl and hydroxyl be more than 3 hydroxyl acids.As the example of such hydroxyl acids, Hydroxy M Phthalic Acid, hydroxyterephthalic acid, dihydric para-phthalic acid, trihydroxy terephthalic acid (TPA) etc. can be listed.

In addition, also suitable be used in these polyfunctional monomers the hydroxyl acids such as carboxyl terminal addition l-lactide, d-lactide, hydroxybenzoic acid and derivative, the multiple materials be formed by connecting of this hydroxyl acids etc. and the compound that obtains.

They can be used alone a kind, as required, and also can by multiple and use.

In polyester feed stock resin in the present invention, from the Component units of polyfunctional monomer in polyester feed stock resin containing the whole Component units of ratio relative to the polyester in polyester feed stock resin, be preferably more than 0.005 % by mole and less than 2.5 % by mole.The ratio that contains from the Component units of polyfunctional monomer is more preferably more than 0.020 % by mole and less than 1 % by mole, more preferably more than 0.025 % by mole and less than 1 % by mole, more preferably more than 0.035 % by mole and less than 0.5 % by mole, be particularly preferably more than 0.05 % by mole and less than 0.5 % by mole, most preferably be more than 0.1 % by mole and less than 0.25 % by mole.

Can the Component units of above polyfunctional monomer from 3 officials by making to exist in polyester feed stock resin, as described above, when polyester film is shaped the most at last, the composition be not formed at coating by the functional group that uses in polycondensation in the coating layer on polyester film produces hydrogen bond, covalent bond, thus the adhesiveness of coating layer and polyester film is kept more well, the generation of peeling off effectively can be prevented.In addition, obtain the Component units of above polyfunctional monomer to branch out the structure of polyester molecule chain by from 3 officials, the mutual winding between polyester molecule can be promoted.

In esterification and/or ester exchange reaction, known catalysts all the time can be used.As this catalysts, alkali metal compound, alkaline earth metal compound, zinc compound, lead compound, manganese compound, cobalt compound, aluminium compound, antimonial, titanium compound, phosphorus compound etc. can be listed.Usually, in the arbitrary stage preferably before the manufacture method of polyester completes, antimonial, germanium compound, titanium compound is added as polymerization catalyst.As such method, if getting such as germanium compound is example, then preferably directly add germanium compound powder.

Aromatic dicarboxylic acid and aliphatic diol are polymerized by such as esterification operation under the existence of the catalyst containing titanium compound.In this esterification operation, as the titanium compound of catalyst, use organic chelated titanium complex using organic acid as part, at least arrange in operation simultaneously add successively organic Ti chelator complex compound, magnesium compound, do not have aromatic rings alternatively the phosphate of 5 valencys of base process and form.

First, before interpolation magnesium compound and phosphorus compound, by aromatic dicarboxylic acid and aliphatic diol and the catalyst mix containing titanium compound and organic chelated titanium complex.Because the titanium compounds such as organic chelated titanium complex also have high catalytic activity relative to esterification, so esterification can be carried out well.Now, adding titanium compound by the process of dicarboxylic acid component and diol component mixing, after also dicarboxylic acid component (or diol component) can being mixed with titanium compound, diol component (or dicarboxylic acid component) can be mixed.In addition, dicarboxylic acid component can also be mixed with titanium compound with diol component simultaneously.Mixing is not particularly limited its method, can be undertaken by known method.

Preferred polyester is PETG (PET), poly-NDA glycol ester (PEN), more preferably PET.And then, PET preferably uses the one kind or two or more material be polymerized be selected from germanium (Ge) series catalysts, antimony (Sb) series catalysts, aluminium (Al) series catalysts and titanium (Ti) series catalysts, is more preferably Ti series catalysts.

The reactivity of Ti series catalysts is high, can reduce polymerization temperature.Therefore, particularly can suppress polyester generation thermal decomposition in the polymerization and produce COOH.That is, by using Ti series catalysts, the amount of the terminal carboxylic of the polyester of the reason becoming thermal decomposition can be reduced, foreign matter can be suppressed to be formed.By reducing the amount of the terminal carboxylic of polyester, polyester film generation thermal decomposition after manufacture polyester film can also be suppressed.

As Ti series catalysts, oxide, hydroxide, alkoxide, carboxylate, carbonate, oxalates, organic chelated titanium complex and halide etc. can be listed.As long as Ti series catalysts does not damage the scope of effect of the present invention, then also two or more titanium compounds can be used.

As the example of Ti series catalysts, metatitanic acid four n-propyl can be listed, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, metatitanic acid four tert-butyl ester, metatitanic acid four cyclohexyl, metatitanic acid tetraphenyl ester, the Titanium alkoxides such as metatitanic acid tetrabenzyl ester, the titanium oxide obtained by the hydrolysis of Titanium alkoxides, by the hydrolysis of the mixture of Titanium alkoxides and silicon alkoxide or zirconium alkoxide and the titanium-silicon obtained or zirconium mixed oxide, acetic acid titanium, titanium oxalate, titanium potassium oxalate, titanium oxalate sodium, potassium titanate, sodium titanate, metatitanic acid-alumag, titanium chloride, titanium chloride-aluminum chloride mixture, titanium acetylacetone, using organic acid as the organic chelated titanium complex etc. of part.

When being polymerized by polyester, preferably below 50ppm, more preferably below 30ppm, preferably further the titanium of catalyst (Ti) compound is used as to be polymerized in the scope of below 15ppm at more than 3ppm at more than 2ppm in titanium elements scaled value at more than 1ppm.In this case, in polyester feed stock resin, containing more than 1ppm and the titanium elements of below 50ppm.

If the amount of the titanium elements comprised in polyester feed stock resin is more than 1ppm, then the weight average molecular weight (Mw) of polyester rises, and is difficult to thermal decomposition occurs.Therefore, in extruder, foreign matter reduces.If the amount of the titanium elements comprised in polyester feed stock resin is below 50ppm, then Ti series catalysts is difficult to become foreign matter, and when the stretching of polyester film, stretching inequality is alleviated.

[titanium compound]

As the titanium compound of catalyst component, preferably use at least a kind of the organic chelated titanium complex using organic acid as part.As organic acid, such as citric acid, lactic acid, trimellitic acid, malic acid etc. can be listed.Wherein, preferably using citric acid or citrate as the organic chelated complex compound of part.

When using Ti chelator complex compound such as using citric acid as part, the generation of the foreign matters such as minuteness particle is few, compared with other titanium compound, can obtain polymerization activity and the good polyester of tone.And then when using citric acid Ti chelator complex compound, the method also by carrying out adding in the stage of esterification, compared with the situation of carrying out after esterification adding, can obtain polymerization activity and tone well and the few polyester of terminal carboxyl group.About this point, presumption titanium catalyst also has the catalytic effect of esterification, by adding in Esterification Stage, oligomer acid number step-down at the end of esterification, later polycondensation reaction is more effectively carried out, in addition high as being hydrolyzed patience compared with the complex compound of part and Titanium alkoxides etc. using citric acid, can not be hydrolyzed in esterification reaction process, the catalyst as esterification and polycondensation reaction under the state maintaining original activity plays function efficiently.

In addition, known general terminal carboxyl group amount more at most hydrolytic resistance more worsens, but terminal carboxyl group quantitative change is few by above-mentioned adding method, thus can expect the raising of hydrolytic resistance.

As citric acid Ti chelator complex compound, such as, the commercially available product such as VERTECAC-420 as JohnsonMatthey Inc. can easily obtain.

Aromatic dicarboxylic acid and aliphatic diol can comprise their slurry by preparation, and it are supplied to continuously in esterification operation and import.

In addition, as titanium compound, except organic chelated titanium complex, generally, oxide, hydroxide, alkoxide, carboxylate, carbonate, oxalates and halide etc. can be listed.As long as do not damage the scope of effect of the present invention, then except organic chelated titanium complex, can also and with other titanium compound.

As the example of such titanium compound, metatitanic acid four n-propyl can be listed, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, metatitanic acid four tert-butyl ester, metatitanic acid four cyclohexyl, metatitanic acid tetraphenyl ester, the Titanium alkoxides such as metatitanic acid tetrabenzyl ester, the titanium oxide obtained by the hydrolysis of Titanium alkoxides, by the hydrolysis of the mixture of Titanium alkoxides and silicon alkoxide or zirconium alkoxide and the titanium-silicon obtained or zirconium mixed oxide, acetic acid titanium, titanium oxalate, titanium potassium oxalate, titanium oxalate sodium, potassium titanate, sodium titanate, metatitanic acid-alumag, titanium chloride, titanium chloride-aluminum chloride mixture, titanium acetylacetone etc.

In the present invention, the manufacture method of the polyester formed preferably by arranging following operation makes, described operation is: esterification operation, while aromatic dicarboxylic acid and aliphatic diol are carried out being polymerized under the existence of the catalyst containing titanium compound, the at least one of titanium compound is the organic chelated titanium complex using organic acid as part, at least comprises the process of adding organic Ti chelator complex compound, magnesium compound successively and not having the aromatic rings alternatively phosphate of 5 valencys of base; And polycondensation step, make the esterification reaction product generated in esterification operation carry out polycondensation reaction and generate condensation polymer.

In this case, in the process of esterification, by be set in there is organic Ti chelator complex compound as titanium compound during add magnesium compound, then the order of addition of the phosphorus compound of specific 5 valencys is added, thus the reactivity of titanium catalyst can be kept in appropriateness highland, give the electrostatic come by magnesium ribbon and apply characteristic, and effectively suppress the decomposition reaction in polycondensation, thus result be can obtain painted less, there is the improved polyester of xanthochromia when high electrostatic applies characteristic and is exposed under high temperature.

Thus, painted during painted and subsequent melting masking when can provide polymerization tails off, compared with the polyester of antimony (Sb) catalyst system in the past yellow feel alleviate, in addition, there is tone, the transparency that the polyester of the germanium catalyst system higher unlike the transparency is inferior, and the polyester of excellent heat resistance.In addition, can obtain when not using cobalt compound, pigment isochrome key whole timber material that there is the high transparency, yellow feels few polyester.

This polyester can be used in the high purposes of the requirement relevant with the transparency (such as optical film, industrial lithographic printing etc.), owing to there is no need the germanium series catalysts using high price, reduces so can seek significantly cost.In addition, due to being mixed into of foreign matter resulting from catalyst easily produced by Sb catalyst system can also be avoided, so the generation of fault in film-forming process, quality is bad alleviates, can also seek to be improved by yield and the cost degradation that brings.

When carrying out esterification, the process of the phosphorus compound of the organic chelated titanium complex as titanium compound, the magnesium compound as additive and 5 valencys is added in preferred setting successively.Now, under the existence of organic chelated titanium complex, esterification can be carried out, then start to add magnesium compound before interpolation phosphorus compound.

[phosphorus compound]

As the phosphorus compound of 5 valencys, use at least one without the aromatic rings alternatively phosphate of 5 valencys of base.Can list and such as there is the phosphate ((OR) that carbon number is the low alkyl group alternatively base of less than 2 ₃-P=O; R=carbon number is the alkyl of 1 or 2), specifically, particularly preferably trimethyl phosphate, triethyl phosphate.

As the addition of phosphorus compound, preferred P element scaled value reaches more than 50ppm and the amount of the scope of below 90ppm.The amount of phosphorus compound more preferably reaches more than 60ppm and the amount of below 80ppm, more preferably reaches more than 60ppm and the amount of below 75ppm.

[magnesium compound]

By comprising magnesium compound in the polyester, the electrostatic imposing of polyester improves.In this case, although easily painted, in the present invention, can suppress painted and obtain excellent tone, heat resistance.

As magnesium compound, the magnesium salts such as such as magnesia, magnesium hydroxide, magnesium alkoxide, magnesium acetate, magnesium carbonate can be listed.Wherein, from the deliquescent viewpoint in ethylene glycol, most preferably magnesium acetate.

As the addition of magnesium compound, in order to give high electrostatic imposing, preferred Mg element scaled value reaches the amount of more than 50ppm, more preferably reaches more than 50ppm and the amount of the scope of below 100ppm.The addition of magnesium compound preferably reaches more than 60ppm and the amount of the scope of below 90ppm in imparting electrostatic imposing, more preferably reaches more than 70ppm and the amount of the scope of below 80ppm.

In esterification operation, the mode particularly preferably meeting following relational expression (ii) according to the value Z calculated by following formula (i) is added the titanium compound as catalyst component and the magnesium compound as additive and phosphorus compound and makes the situation of its melt polymerization.Wherein, P content is carry out the self-contained phosphorus amount without the phosphorus compound entirety of the phosphate of 5 valencys of aromatic rings, and Ti content is the titanium amount from the Ti compound entirety comprising organic Ti chelator complex compound.Like this, by select the magnesium compound that comprises in the catalyst system of titanium compound and phosphorus compound and use, and control its interpolation opportunity and adding proportion, thus the catalytic activity of titanium compound can be maintained in appropriateness highland, the tone that yellow sense is few can be obtained simultaneously, even if under (during melting) etc. is exposed to high temperature during masking when polymerisation or thereafter, also can gives and not easily produce yellow painted heat resistance.

(i) Z=5 × (P content [ppm]/P atomic weight)-2 × (Mg content [ppm]/Mg atomic weight)-4 × (Ti content [ppm]/Ti atomic weight)

(ii)0≤Z≤+5.0

Because phosphorus compound not only acts on titanium, but also interact with magnesium compound, so it is the index of the balance as embodiment quantitatively.

Formula (i) embodies from the whole phosphorus amounts that can react, deduct the phosphorus amount acting on magnesium and the formula that can act on the amount of the phosphorus of titanium.When value Z is positive, hindering the phosphorus of titanium to be in superfluous situation, on the contrary, when for negative, being in the situation in order to hinder the phosphorus deficiency needed for titanium.In the reaction, due to each 1 atom of Ti, Mg, P and non-equivalence, so each the molal quantity in through type is multiplied by valence mumber and is weighted.

In the present invention, do not need special synthesis etc., use cheapness and the titanium compound, phosphorus compound, the magnesium compound that easily obtain, can obtain there is the necessary reactivity of reaction and the polyester feed stock resin of tone and the painted patience excellence relative to heat.

In formula (ii), under the state keeping polymerisation reactivity, from the view point of improving tone and the painted patience relative to heat further, preferably meeting the situation of+1.0≤Z≤+ 4.0, more preferably meeting the situation of+1.5≤Z≤+ 3.0.

As the preferred mode in the present invention, can list with under type: before esterification terminates, add in aromatic dicarboxylic acid and aliphatic diol count more than 1ppm with Ti element scaled value and below 30ppm using citric acid or citrate after the Ti chelator complex compound of part, under the existence of this Ti chelator complex compound, add and count more than 60ppm and the magnesium salts of the weak acid of below 90ppm (being more preferably more than 70ppm and below 80ppm) with Mg element scaled value, add further afterwards in this interpolation and count more than 60ppm with P element scaled value and the phosphate without aromatic rings alternatively 5 valencys of base of below 80ppm (being more preferably more than 65ppm and below 75ppm).

In above-mentioned, about Ti chelator complex compound (organic chelated titanium complex) and magnesium salts (magnesium compound) and 5 valencys phosphate separately, preferably more than the 70 quality % of the total addition level mode of adding in order separately.

Esterification can use the multi-stag device be connected in series by least 2 reactors, under carrying out the condition refluxed, removing the water generated by reacting or alcohol to outside system, being implemented simultaneously at ethylene glycol.

In addition, above-mentioned esterification can be carried out with a stage, also can be divided into multiple stage to carry out.

When carrying out esterification with a stage, esterification reaction temperature is preferably 230 ~ 260 DEG C, is more preferably 240 ~ 250 DEG C.

When be divided into multiple stage carry out esterification, the temperature of the esterification of the first reactive tank is preferably 230 ~ 260 DEG C, and be more preferably 240 ~ 250 DEG C, pressure is preferably 1.0 ~ 5.0kg/cm ², be more preferably 2.0 ~ 3.0kg/cm ².The temperature of the esterification of the second reactive tank is preferably 230 ~ 260 DEG C, and be more preferably 245 ~ 255 DEG C, pressure is preferably 0.5 ~ 5.0kg/cm ², be more preferably 1.0 ~ 3.0kg/cm ².When be divided into further more than 3 stages implement, the condition of the esterification in interstage is preferably set to the condition between the first reactive tank and end reaction groove.

-polycondensation-

Polycondensation is that the esterification reaction product making to generate in the esterification reaction carries out polycondensation reaction and generates condensation polymer.Polycondensation reaction can be carried out with 1 stage, also can be divided into multiple stage to carry out.

The esterification reaction products such as the oligomer generated in the esterification reaction are next for polycondensation reaction.This polycondensation reaction can be carried out aptly by being supplied in multistage polycondensation reaction groove.

Such as, about polycondensation reaction condition when carrying out in the reactive tank in 3 stages, preferably the reaction temperature of the first reactive tank is 255 ~ 280 DEG C, is more preferably 265 ~ 275 DEG C, and pressure is 100 ~ 10torr (13.3 × 10 ^-3~ 1.3 × 10 ^-3mPa) 50 ~ 20torr (6.67 × 10, is more preferably ^-3~ 2.67 × 10 ^-3mPa), the reaction temperature of the second reactive tank is 265 ~ 285 DEG C, is more preferably 270 ~ 280 DEG C, and pressure is 20 ~ 1torr (2.67 × 10 ^-3~ 1.33 × 10 ^-4mPa) 10 ~ 3torr (1.33 × 10, is more preferably ^-3~ 4.0 × 10 ^-4mPa), the reaction temperature of the 3rd reactive tank in end reaction groove is 270 ~ 290 DEG C, is more preferably 275 ~ 285 DEG C, and pressure is 10 ~ 0.1torr (1.33 × 10 ^-3~ 1.33 × 10 ^-5mPa) 5 ~ 0.5torr (6.67 × 10, is more preferably ^-4~ 6.67 × 10 ^-5mPa) mode.

In the polyester feed stock resin synthesized as described above, can also further containing Photostabilised dose, antioxidant, ultra-violet absorber, the additive such as fire retardant, easily lubrication prescription (particulate), nucleator (crystallization agent), crystallization Inhibitors.

In the present invention, from the view point of the hydrolytic resistance of polyester film, the inherent viscosity (IV) of polyester feed stock resin is preferably more than 0.55dL/g and below 0.90dL/g.Wherein, be more preferably more than 0.60dL/g and below 0.80dL/g, more preferably more than 0.62dL/g and below 0.78dL/g, most preferably be more than 0.63dL/g and below 0.78dL/g.

Inherent viscosity (IV) is by by solution viscosity (η) and solvent viscosity (η ₀) ratio η _r(=η/η ₀; Relative viscosity) deduct 1 and specific viscosity (the η obtained _sp=η _r-1) value obtained divided by concentration is extrapolated to the value that obtains of state that concentration is zero.IV uses Ubbelohde viscometer, is dissolved in by polyester in 1,1,2,2-tetrachloroethanes/phenol (=2/3 [mass ratio]) mixed solvent, is tried to achieve by the solution viscosity of 25 DEG C.

(melt extruding)

In film forming process in the present invention, the polyester feed stock resin obtained operating as described above melt extrudes, and carries out further cooling and being shaped by polyester film.

With regard to the melt extruding of polyester feed stock resin, such as, use the extruder possessing the screw rod of more than 1 or 2, be heated to the temperature of more than the fusing point of polyester feed stock resin, make screw rod rotation carry out melting mixing and carry out simultaneously.Polyester feed stock resin by heating and utilizing the mixing of screw rod, melting in extruder and become melt.In addition, from the view point of the thermal decomposition suppressed in extruder (poly-ester hydrolysis), preferably after carrying out nitrogen displacement in extruder, melt extruding of polyester feed stock resin is carried out.Extruder is from the viewpoint of the preferred double screw extruder suppressing melting temperature lower.

The polyester feed stock resin (melt) of melting is extruded from extrusion die through gear pump, filter etc.Extrusion die is also referred to as " mould " (with reference to JISB8650:2006, a) extrusion shaper, numbering 134).

Now, melt can be extruded with individual layer, also can with multilayer extrusion.

In polyester feed stock resin, preferably containing the end-capping reagent in Xuan Zi oxazoline based compound, carbon imide compound and epoxide.In this case, in film forming process, the polyester feed stock resin being added with end-capping reagent is melted mixing, by when melting mixing and the polyester feed stock resin that reacts of end-capping reagent melt extrude.

Make by arranging the operation comprising end-capping reagent in polyester feed stock resin, weatherability improves, and can suppress thermal contraction lower.In addition, when being shaped by polyester film, it is large that the end section being bonded to polyester end and strand becomes volume, and the micro concavo-convex amount on film surface increases, so easily embody Anchoring Effect, polyester film improves with the adhesion of the coating layer that coating is formed on this film.

As long as the interpolation of end-capping reagent is melted the mixing stage period from the process till extruding of putting into of raw material together with polyester feed stock resin, then be not particularly limited, but end-capping reagent preferably after raw material is dropped into rotating cylinder, deliver to ventilating opening with screw rod before during add, and for melting mixing together with material resin.Such as the supply port supplying end-capping reagent is set between the material pouring inlet of rotating cylinder carrying out melting mixing and ventilating opening, can directly joins in the material resin in rotating cylinder.Now, end-capping reagent can be added to hot milling to start but not to reach completely in the polyester feed stock resin of molten condition, also can be added in the polyester feed stock resin (melt) of molten condition.

As the amount relative to polyester feed stock resin of end-capping reagent, be preferably more than 0.1 quality % and below 5 quality % relative to the gross mass of polyester feed stock resin.End-capping reagent be more than 0.3 quality % and below 4 quality % relative to the preferred amount of polyester feed stock resin, more preferably more than 0.5 quality % and below 2 quality %.

Be more than 0.1 quality % by what make end-capping reagent containing ratio, not only can reach and reduce the weatherability brought of effect by AV and improve, low thermal shrinkage behavior and adhesiveness can also be given.In addition, if end-capping reagent is below 5 quality % containing ratio, then except adhesiveness improves, the reduction of the glass transition temperature (Tg) of the polyester caused because of the interpolation of end-capping reagent can also be suppressed, the reduction of the weatherability caused thus, the increase of thermal contraction can be suppressed.This is because, the reactivity of the relatively polyester because Tg reduces can be suppressed to increase and the water-disintegrable increase that produces, the motility of the polyester molecule increased because Tg reduces can be suppressed to become easy increase and the thermal contraction that produces.

Carbon imide compound, epoxide, are Ji the details such as the illustration of oxazoline based compound and preferred mode is as already described in the item of " polyester film ".

By being extruded to curtain coating drum by melt (polyester) from mould, can be shaped (curtain coating process) is for membranaceous.

The thickness of the membranaceous polyester formed body obtained by curtain coating process is preferably 0.1mm ~ 3mm, is more preferably 0.2mm ~ 2mm, more preferably 0.3mm ~ 1.5mm.

By the thickness of membranaceous polyester formed body is set to below 3mm, the cooling caused because of the accumulation of heat of melt can be avoided to postpone, in addition, by being set to more than 0.1mm, from during being expressed into cooling, OH base in polyester, COOH basal orientation polyester diffusion inside, suppress the OH base of the main cause becoming hydrolysis generation and COOH base to expose in surface of polyester.

The method of the melt cooling extruded from extrusion die is not particularly limited, as long as blow cold wind to melt, contact or spray water with curtain coating drum (cooling curtain coating drum).Cooling means only can carry out a kind, also two or more combination can be carried out.

About cooling means, in above-mentioned, from the view point of the attachment preventing oligomer to film surface when operating continuously, preferably utilize the cooling of cold wind and employ at least one in the cooling of curtain coating drum.And then, the melt cold front heavy rain particularly preferably will extruded from extruder, and make melt contact with curtain coating drum and cool.

In addition, cooling component is waited to strip using the polyester formed body of the coolings such as curtain coating drum to use angle stripper etc. to strip component from curtain coating drum.

(longitudinal stretching operation)

In longitudinal stretching operation of the present invention, the polyester film utilizing film forming process to be shaped is carried out longitudinal stretching along its length.

The longitudinal stretching of film such as can by by the 1 pair niproll of film through clamping film, along the length direction conveyance film of film, applies tension force to carry out between the above niproll of 2 couple arranged along the conveyance direction of film simultaneously.Specifically, such as 1 couple of niproll A is set at the conveyance direction upstream side of film, when 1 couple of niproll B is set in downstream, when transporting film, by making the rotating speed of the niproll A of the rotating ratio upstream side of the niproll B in downstream fast, thus film is stretched along conveyance direction (MD direction).In addition, also 2 can be arranged respectively independently of one another in upstream side, downstream to above niproll.In addition, the longitudinal stretching of polyester film also can use the longitudinal tensile fixture possessing above-mentioned niproll to carry out.

In longitudinal stretching operation, the longitudinal stretching multiplying power of polyester film is preferably 2 ~ 5 times, is more preferably 2.5 ~ 4.5 times, more preferably 2.8 ~ 4 times.

In addition, be preferably 6 times ~ 18 times of the area of the polyester film before stretching with the area stretch multiplying power of the product representation of stretching ratio in length and breadth, be more preferably 8 times ~ 17.5 times, more preferably 10 times ~ 17 times.

Temperature during longitudinal stretching about polyester film is (following, also referred to as " longitudinal drawing temperature "), when setting the glass transition temperature of polyester film as Tg, be preferably more than Tg-20 DEG C and less than Tg+50 DEG C, be more preferably more than Tg-10 DEG C and less than Tg+40 DEG C, more preferably more than Tg DEG C and less than Tg+30 DEG C.

In addition, as the means of heating polyester film, when rollers such as using niproll stretches, by arranging in roller inside the pipe arrangement that heater maybe can flow through hot solvent, and the polyester film contacted with roller can be heated.In addition, when not using roller, also can by blowing hot blast to polyester film, contacting with thermals source such as heaters or near thermal source, polyester film heated.

In the manufacture method of polyester film of the present invention, comprise the cross directional stretch operation described later being different from longitudinal stretching operation.Therefore, in the manufacture method of polyester film of the present invention, become and polyester film is stretched along the length direction (conveyance direction, MD) of polyester film and at least 2 axles in the direction vertical with the length direction of polyester film (TD direction).As long as at least carry out 1 time respectively to the stretching in MD direction and TD direction.

In addition, so-called " direction (TD) vertical with the length direction (conveyance direction, MD) of polyester film " refers to the direction of the angle of vertical with the length direction of polyester film (conveyance direction, MD) (90 °), but comprises the direction (being such as the direction of 90 ° ± 5 ° relative to MD direction) can regarding in fact 90 ° due to machine error etc. relative to the angle of length direction (i.e. conveyance direction) as.

As biaxial stretch-formed method, except separately carrying out the successively biaxial stretching method of longitudinal stretching and cross directional stretch, also can be biaxial stretching method while of simultaneously carrying out longitudinal stretching and cross directional stretch, no matter any.Longitudinal stretching and cross directional stretch also can carry out more than 2 times independently of one another, and the order of longitudinal stretching and cross directional stretch is not limit.Such as longitudinal stretching → cross directional stretch, longitudinal stretching → cross directional stretch → longitudinal stretching, longitudinal stretching → stretching mode such as longitudinal stretching → cross directional stretch, cross directional stretch → longitudinal stretching can be listed.Wherein preferred longitudinal stretching → cross directional stretch.

(cross directional stretch operation)

Then, the cross directional stretch operation in the present invention is described in detail.

Cross directional stretch operation in the present invention be by longitudinal stretching after polyester film carry out the operation of cross directional stretch, by being transported by polyester film to following portion successively along the width vertical with length direction:

(a) polyester film after longitudinal stretching is preheated to the temperature that can stretch preheating part,

(b) to through preheating polyester film along the width vertical with length direction apply tension force and carry out the extension section of cross directional stretch,

(c) to the polyester film after carrying out longitudinal stretching and cross directional stretch heat make its crystallization and the thermal finalization portion of thermal finalization,

D () heats the polyester film through thermal finalization, by the tension recovery of polyester film except striping overstrain hot wire-CVD portion and

E cooling end that polyester film after hot wire-CVD cools by (),

In at least one in (c) thermal finalization portion and (d) hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end, TD direction of polyester film, and, in (e) cooling end, the average cooling rate film width end when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to 1.01 times ~ 2 times of average cooling rate in the central portion of film width and carries out this cross directional stretch.

In cross directional stretch operation in the present invention, as long as polyester film with above-mentioned formation by the mode of cross directional stretch, then its concrete means do not limit, but preferably use the transversal stretching device that can carry out the process of each operation forming above-mentioned formation or biaxial stretcher to carry out.

-biaxial stretcher-

As shown in Figure 3, biaxial stretcher 100 possesses 1 couple of annular orbit 60a and 60b and to be installed on each annular orbit and can along the holding component 2a ~ 2l of rail moving.Annular orbit 60a and 60b clamps polyester film 200 and the configuration that is mutually symmetrical, and holding component 2a ~ 2l gripping polyester film 200, making it along rail moving, thus can stretch along film width by utilizing.

The region that biaxial stretcher 100 is formed by following portion is formed, and described each portion is: with polyester film 200 is carried out preheating preheating part 10, polyester film 200 carried out stretching along the direction vertical with arrow MD direction and arrow TD direction and the extension section 20 of tension force, the thermal finalization portion 30 of heating under the state applying tension force to the polyester film being applied with tension force are applied to polyester film, will to heat through the polyester film of thermal finalization and by the hot wire-CVD portion 40 of the tension recovery of the polyester film through thermal finalization and cooling end 50 that the polyester film behind hot wire-CVD portion is cooled.

On annular orbit 60a, being provided with can along holding component 2a, 2b, 2e, 2f, 2i and 2j of annular orbit 60a movement, on this external annular orbit 60b, being provided with can along holding component 2c, 2d, 2g, 2h, 2k and 2l of annular orbit 60b movement.Hold the end that component 2a, 2b, 2e, 2f, 2i and 2j hold the TD direction of polyester film 200, hold another end that component 2c, 2d, 2g, 2h, 2k and 2l hold the TD direction of polyester film 200.Hold component 2a ~ 2l and be commonly referred to as fixture, clip etc.

Hold component 2a, 2b, 2e, 2f, 2i and 2j along annular orbit 60a movement counterclockwise, hold component 2c, 2d, 2g, 2h, 2k and 2l along annular orbit 60b movement clockwise.

Hold the end that component 2a ~ 2d holds polyester film 200 in preheating part 10, move along annular orbit 60a or 60b under the state gripped, the hot wire-CVD portion 40 at stretched portion 20, holding component 2e ~ 2h place, advances to the cooling end 50 holding component 2i ~ 2l place.Afterwards, holding component 2a and 2b and holding component 2c and 2d according to conveyance direction order, moves along annular orbit 60a or 60b further, gets back to preheating part 10 after the end of polyester film 200 is left in the end in the downstream, MD direction of cooling end 50.Now, polyester film 200 moves along arrow MD direction and carries out thermal finalization in the preheating in preheating part 10, the stretching in extension section 20, thermal finalization portion 30, the hot wire-CVD in hot wire-CVD portion 40, the cooling in cooling end 50 successively, by cross directional stretch.Hold the conveyance speed that the translational speed of component 2a ~ 2l in each regions such as preheating part becomes polyester film 200.

Hold component 2a ~ 2l and can change translational speed independently of one another.

Biaxial stretcher 100 can carry out the cross directional stretch stretched along TD direction by polyester film 200 in extension section 20, by changing the translational speed holding component 2a ~ 2l, polyester film 200 can also be stretched along MD direction.That is, biaxial stretch-formed the while of biaxial stretcher 100 also can being used to carry out.

The holding component holding the end in the TD direction of polyester film 200 only illustrates 2a ~ 2l in figure 3, but in order to support polyester film 200, biaxial stretcher 100 is also provided with not shown holding component except 2a ~ 2l.In addition, below, sometimes holding component 2a ~ 2l is generically and collectively referred to as " holding component 2 ".

(a. preheating part)

In preheating part, the polyester film after longitudinal stretching in longitudinal stretching operation is preheated to the temperature that can stretch.

As shown in Figure 3, in preheating part 10 by polyester film 200 preheating.In preheating part 10, heat in advance before being stretched by polyester film 200, the cross directional stretch of polyester film 200 is become can easily carry out.

About the film surface temperature of preheating part end point (hereinafter also referred to as " preheat temperature ".), when setting the glass transition temperature of polyester film 200 as Tg, being preferably Tg-10 DEG C ~ Tg+60 DEG C, being more preferably Tg DEG C ~ Tg+50 DEG C.

In addition, preheating part end point refers to the position that moment, the i.e. polyester film 200 of the preheating terminating polyester film 200 leave from the region of preheating part 10.

(b. extension section)

In extension section, the polyester film to preheating in preheating part applies tension force along the width (TD direction) vertical with length direction (MD direction) and carries out cross directional stretch.

As shown in Figure 3, in extension section 20, the polyester film 200 by preheating at least carries out cross directional stretch along the TD direction vertical with the length direction of polyester film 200 and applies tension force to polyester film 200.

Stretching (cross directional stretch) to the vertical direction (TD) of the length direction (conveyance direction, MD) with polyester film 200 refers to along stretching with the direction of the angle of the length direction (conveyance direction, MD) vertical (90 °) of polyester film 200, but also can be the direction of the scope of machine error.The scope of so-called machine error to regard the direction of the angle (90 ° ± 5 °) vertical with the length direction of polyester film (conveyance direction, MD) as.

In extension section 20, the area stretch multiplying power (each stretching ratio is long-pending) of polyester film 200 is preferably 6 times ~ 18 times of the area of the polyester film 200 before stretching, and is more preferably 8 times ~ 17.5 times, more preferably 10 times ~ 17 times.

In addition, film surface temperature during cross directional stretch about polyester film 200 is (hereinafter also referred to as " transverse drawing temperature ".), when setting the glass transition temperature of polyester film 200 as Tg, being preferably more than Tg-10 DEG C and less than Tg+100 DEG C, being more preferably more than Tg DEG C and less than Tg+90 DEG C, more preferably more than Tg+10 DEG C and less than Tg+80 DEG C.

As mentioned above, hold component 2a ~ 2l and can change translational speed independently of one another.Therefore, such as, also can by making the translational speed of the holding component 2 in the downstream, extension section 20MD direction such as extension section 20, thermal finalization portion 30 faster than the translational speed of the holding component 2 in preheating part 10, and carry out the longitudinal stretching that stretched along conveyance direction (MD direction) by polyester film 200 concurrently.

The longitudinal stretching of the polyester film 200 in cross directional stretch operation can only carry out in extension section 20, also can carry out in thermal finalization portion 30 described later, hot wire-CVD portion 40 or cooling end 50.Also longitudinal stretching can be carried out in multiple position.

(c. thermal finalization portion)

In thermal finalization portion, the polyester film heating after implementing longitudinal stretching and cross directional stretch is made its crystallization and carries out thermal finalization.

So-called thermal finalization to refer under the state applying tension force to polyester film 200 in extension section 20 directly heating and makes crystallizing polyester.

In thermal finalization portion 30 in figure 3, for the polyester film 200 being applied with tension force, being preferably up to of the surface of polyester film 200 is reached film surface temperature (in this description, also referred to as " heat setting temperature ", " T _{thermal finalization}".) control the scope at 160 DEG C ~ 240 DEG C and film is heated.

If heat setting temperature is more than 160 DEG C, then the easy crystallization of polyester, by polyester molecule with elongation state immobilization, can improve the hydrolytic resistance of polyester film.In addition, if heat setting temperature is less than 240 DEG C, then the part owing to being wound around each other at polyester molecule not easily produces slip, and polyester molecule is difficult to shrink, so can suppress the reduction of the hydrolytic resistance of polyester film.In other words, heated by the mode reaching 160 DEG C ~ 240 DEG C according to heat setting temperature, the crystallization generation orientation of polyester molecule can be made, improve the hydrolytic resistance of polyester film.

About heat setting temperature, from above-mentioned same reason, the scope of preferably 170 DEG C ~ 230 DEG C, the scope of more preferably 175 DEG C ~ 225 DEG C.

In addition, be up to that to reach film surface temperature (heat setting temperature) be make thermocouple contact the surface of polyester film 200 and the value that measures.

And then, heat setting temperature is controlled 160 DEG C ~ 240 DEG C time, preferably being up on film width is reached film surface temperature deviation and be set to more than 0.5 DEG C and less than 10.0 DEG C.On film width, be up to that to reach film surface temperature deviation be more than 0.5 DEG C by what make film, during conveyance in rear operation gauffer in be favourable, in addition, by deviation being suppressed below 10.0 DEG C, the deviation of the crystallization degree on width can be suppressed.Thus, the lax difference on film width alleviates, and can prevent the generation of the damage on the face in manufacture process, and hydrolytic resistance improves.

In above-mentioned, reaching film surface temperature deviation about being up to, from reason similar to the above, being more preferably more than 0.5 DEG C and less than 7.0 DEG C, more preferably more than 0.5 DEG C and less than 5.0 DEG C, be particularly preferably more than 0.5 DEG C and less than 4.0 DEG C.

In addition, the heating to film during thermal finalization can only be carried out from the side of film, also can carry out from both sides.Such as, when cooling on curtain coating drum after melt extruding in film forming process, because the polyester film be shaped is different with the face type of cooling of its opposition side in a face, so film becomes easily curling.Therefore, the heating in preferably this heat-setting process carry out in the face contacted with curtain coating drum in film forming process.By the heating surface in heat-setting process being set to the face, the i.e. cooling surface that contact with curtain coating drum, can eliminate curling.

Now, heating preferably according to the surface temperature after the firm heating on the heating surface in heat-setting process and compared with the surface temperature of the non-heated of heating surface opposition side more than 0.5 DEG C and the mode that the scope of less than 5.0 DEG C uprises carry out.The temperature of heating surface during by making thermal finalization is higher than the face of its opposition side, and the temperature difference between its table back of the body is 0.5 ~ 5.0 DEG C, can more effectively eliminate the curling of film.From the view point of curling eradicating efficacy, the temperature difference between heating surface and the non-heated of its opposition side is more preferably the scope of 0.7 ~ 3.0 DEG C, more preferably more than 0.8 DEG C and less than 2.0 DEG C.

In addition, in the present invention, at least one in thermal finalization portion 30 and hot wire-CVD portion 40, heater is utilized to carry out selective radiation heating to the end, TD direction of polyester film.If do not carry out described radiation heating, MD percent thermal shrinkage on the TD direction of then made polyester film can not decline, the distribution of MD percent thermal shrinkage and the variable quantity of MD percent thermal shrinkage can not diminish, and meet already described formula (I) and the film of (II) so cannot manufacture.

When radiation heating being carried out to the end, TD direction of film in hot wire-CVD portion 40, the radiation heating in thermal finalization portion 30 can be omitted, also can carry out in both thermal finalization portion 30 and hot wire-CVD portion 40.

Wherein, so-called " end, TD direction of polyester film " refers to the region 10% of the total length (namely, width) in the edge at the two ends in the TD direction of polyester film and the TD direction from edge to polyester film.

The heating of the end, TD direction of polyester film uses can the heater of radiation heating be carried out, and carries out selective heating at least one end in the TD direction of polyester film.From the view point of the MD thermal contraction suppressing local, preferably the both ends in the TD direction of polyester film are heated.In addition, so-called " selective heating " not heats the film entirety of the end comprising polyester film, and refers to and heat partly film end.

As can the heater of radiation heating, such as infrared heater can be listed, particularly preferably use the heater (ceramic heater) of pottery system.

The heating of the end, TD direction of polyester film preferably adjusts the surface temperature of heater and polyester film surface and the distance (air line distance) of heater and carries out.

When the surface temperature of heater is 300 DEG C ~ 800 DEG C, preferably polyester film surface is set to 20mm ~ 250mm with the distance of heater, more preferably heater surface temperatures is 400 DEG C ~ 700 DEG C and the distance between film-heater is set to 50mm ~ 200mm.

In addition, when carrying out radiation heating, preferably the temperature deviation on film TD direction being contracted to more than 0.7 DEG C and the scope of less than 3.0 DEG C, the deviation of the crystallization degree on film width can being alleviated the scope to less than more than 0.5% ~ 3.0% thus.Like this, the increase and decrease of the local of MD percent thermal shrinkage can be suppressed, the generation that muscle shape swells can be suppressed, hydrolytic resistance can be improved further simultaneously.

When heating in thermal finalization portion, preferably the holdup time in thermal finalization portion is set to more than 5 seconds and less than 50 seconds.The so-called holdup time be film in thermal finalization portion by time that the state heated continues.If the holdup time is more than 5 seconds, then because the crystallization degree relative to the heat time diminishes, so the crystallization degree deviation ratio of width more not easily produce in be favourable, if less than 50 seconds in addition, then owing to there is no need the linear velocity extremely reducing stenter, so be favourable in productivity ratio.

Wherein, about the holdup time, from above-mentioned same reason, preferably more than 8 seconds and less than 40 seconds, more preferably more than 10 seconds and less than 30 seconds.

In the present invention, at least one in thermal finalization portion and hot wire-CVD portion, radiation heating is carried out to polyester film end, but also can carry out the selective radiation heating of film end further in both preheating part or extension section or preheating part and extension section.

Be the heating of the deviation alleviating temperature deviation on the TD direction of film and crystallization degree to the radiation heating of the end, TD direction of polyester film, become the increase and decrease of the local easily suppressing MD percent thermal shrinkage.

(d. hot wire-CVD portion)

In hot wire-CVD portion, the polyester film through thermal finalization is heated, by the tension recovery of polyester film except the overstrain of striping.

As mentioned above, in the manufacture method of polyester film of the present invention, at least one in thermal finalization portion and hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end, TD direction of polyester film.As long as the selective radiation heating of the end, TD direction of the polyester film in hot wire-CVD portion heats same method to carry out by the selective radiation of the end, TD direction with the polyester film in thermal finalization portion, the number range of heating-up temperature and preferred mode are too.

But hot wire-CVD is by the polyester film heating through thermal finalization and the tension force of lax polyester film, and being preferably as follows the heating of polyester film in hot wire-CVD portion is carried out.

In hot wire-CVD portion 40 in figure 3, preferably reach being up to of polyester film 200 that film surface temperature reaches in specific heat setting section 30 reach film surface temperature (T according to being up to of surface of polyester film 200 _{thermal finalization}) mode of temperature of low more than 5 DEG C mode that polyester film 200 is heated.

Below, being also up to of the surface of the polyester film 200 during hot wire-CVD is reached film surface temperature and be called " hot wire-CVD temperature (T _{hot wire-CVD}) ".

In hot wire-CVD portion 40, by making hot wire-CVD temperature (T _{hot wire-CVD}) than heat setting temperature (T _{thermal finalization}) temperature (T of low more than 5 DEG C _{hot wire-CVD}≤ T _{thermal finalization}-5 DEG C) carry out heating to remove tension force (reduction tensile stress), the dimensional stability of polyester film can be improved further.

If T _{hot wire-CVD}for " T _{thermal finalization}-5 DEG C " below, then the hydrolytic resistance of polyester film is more excellent.In addition, T _{heat pine} _relaxdimensional stability become good in be preferably more than 100 DEG C.

And then, T _{hot wire-CVD}be preferably more than 100 DEG C and compare T _{thermal finalization}the temperature province of low more than 15 DEG C (100 DEG C≤T _{hot wire-CVD}≤ T _{thermal finalization}-15 DEG C), be more preferably more than 110 DEG C and compare T _{thermal finalization}the temperature province of low more than 25 DEG C (110 DEG C≤T _{hot wire-CVD}≤ T _{thermal finalization}-25 DEG C), be particularly preferably more than 120 DEG C and compare T _{thermal finalization}the temperature province of low more than 30 DEG C (120 DEG C≤T _{hot wire-CVD}≤ T _{thermal finalization}-30 DEG C).

In addition, T _{hot wire-CVD}it is the value measured by making the surface of thermocouple contact polyester film 200.

(e. cooling end)

In cooling end, by the polyester film cooling after hot wire-CVD in hot wire-CVD portion.

As shown in Figure 3, in cooling end 50, the polyester film 200 behind hot wire-CVD portion 40 is cooled.By cooling by warmed-up polyester film 200 in thermal finalization portion 30 or hot wire-CVD portion 40, thus being finalized of shape of polyester film 200.

The temperature on the surface (face) of the polyester in the cooling end exit of the polyester 200 in cooling end 50 is (hereinafter also referred to as " chilling temperature ".) preferably low than the glass transition temperature Tg+50 DEG C of polyester film 200.Specifically, be preferably 25 DEG C ~ 110 DEG C, be more preferably 25 DEG C ~ 95 DEG C, more preferably 25 DEG C ~ 80 DEG C.By making chilling temperature be above-mentioned scope, can prevent removing clip holding caudacoria and shrinking unevenly.

Wherein, the end of the cooling end 50 when the outlet of so-called cooling end refers to that polyester 200 leaves from cooling end 50, refers to the position when holding component 2 (in Fig. 3, holding component 2j and 2l) holding polyester film 200 leaves polyester film 200.

And then, in cooling end 50, preferably average cooling rate when making the temperature on the surface of polyester film (face) be cooled to 70 DEG C from 150 DEG C is set to the scope of 2 DEG C/sec ~ 100 DEG C/sec.

Wherein, average cooling rate is tried to achieve by utilizing the film temperature of the film in radiation thermometer actual measurement cooled region.That is, reach by film temperature conveyance speed Sm/ that the place of 150 DEG C and film temperature reach the distance Zm in the place of 70 DEG C and film and to obtain cool time (Z ÷ S) second from 150 to 70 DEG C second.By calculating (150-70) ÷ (Z ÷ S) further by it, obtain average cooling rate.

By average cooling rate is set to more than 2 DEG C/sec, the cooling of the polyester film in stretching device can be suppressed not enough, the cohesive step-down of polyester film.Therefore, in the operation after leaving polyester film from cooling end outlet, become not easily produce on roller that polyester film adhesive transports to film etc. fault.In addition, by average cooling rate is set to less than 100 DEG C/sec, the chilling of polyester film can be prevented, in face, not easily produce residual stress inequality, percent thermal shrinkage deviation can be suppressed, become and not easily produce muscle shape protuberance.

Average cooling rate is more preferably 4 DEG C/sec ~ 80 DEG C/sec, more preferably 5 DEG C/sec ~ 50 DEG C/sec.

But in the manufacture method of polyester film of the present invention, the average cooling rate of the film in cooling end is different in the central portion of film width end and film width (TD direction).Specifically, the average cooling rate in film width end is set to 1.01 times ~ 2 times of the average cooling rate in the central portion of film TD direction.Thus, reduce the variation of the trickle MD percent thermal shrinkage of polyester film, become the muscle shape protuberance easily suppressing polyester film.

More than 1.01 times are set to and less than 2 times by the multiplying power (also referred to as specific circulating ratio) of the average cooling rate relative to film TD direction central portion by the average cooling rate in film width end, become the thinner polyester film easily manufacturing and meet formula (I) and (II), easily suppress the generation of muscle shape protuberance.

Specific circulating ratio is preferably 1.03 times ~ 1.7 times, is more preferably 1.05 times ~ 1.5 times.

In preheating in cross directional stretch operation, stretching, thermal finalization, hot wire-CVD and cooling, as the temperature-controlled process that polyester film 200 is heated or cools, can list and hot blast or cold wind are blowed to polyester film 200, make polyester film 200 and can control temperature metallic plate surface contact or near metallic plate.

(recovery of film)

Polyester film 200 chilled in refrigerating work procedure is cut away the grip portion gripped with clip at two ends, TD direction, batch with roll.

In cross directional stretch operation, in order to improve hydrolytic resistance and the dimensional stability of manufactured polyester film further, carry out the lax of the polyester film stretched preferably by method below.

In the present invention, preferably after longitudinal stretching operation, carry out cross directional stretch operation, in cooling end 50, then carry out the lax of MD direction.That is,

At least two holding components are used to hold the both ends of the width (TD) of polyester film 200 at preheating part 10 to an end.Such as, hold the side of an end of the width (TD) of polyester film 200 with holding component 2a and 2b, hold opposite side with holding component 2c and 2d.Then, by making holding component 2a ~ 2d move, polyester film 200 is transported to cooling end 50 from preheating part 10.

In described conveyance, other holding component 2a (2c) by the holding component 2a (2c) of an end of the width (TD direction) with the holding polyester film 200 in preheating part 10 and being adjacent to hold compared with the interval of component 2b (2d), the holding component 2a (2c) of an end of the width of the holding polyester film 200 in constriction cooling end 50 and being adjacent to hold component 2a (2c) other hold the interval of component 2b (2d), thus reduce the conveyance speed of polyester film 200.By described method, the lax of MD direction can be carried out in cooling end 50.

The lax of the MD direction of polyester film 200 can carry out at least one position of thermal finalization portion 30, hot wire-CVD portion 40 and cooling end 50.

As mentioned above, narrow than MD direction upstream side by making the interval between holding component 2a-2b and being interposed between downstream between holding between component 2c-2d, the lax of the MD direction of polyester film 200 can be carried out.Therefore, when carrying out MD direction lax in thermal finalization portion 30 or hot wire-CVD portion 40, as long as when holding component 2a ~ 2d and arriving thermal finalization portion 30 or hot wire-CVD portion 40, slow down and hold the translational speed of component 2a ~ 2d, reduce the conveyance speed of polyester film 200, make the interval between holding component 2a-2b and the interval between holding component 2c-2d narrower than the interval in preheating part.

The conveyance speed of preferred polyester film and the width (total length in the TD direction of film) of polyester film meet lower relation of plane.

Namely, the width L2 of the polyester film the end of the cooling end that the width L1 of the polyester film when width of the polyester film in preferred cross directional stretch operation reaches maximum and polyester film leave from cooling end meets following formula (1), further, the conveyance speed S2 of the polyester film in the conveyance speed S1 of the polyester film in preheating part and the end of cooling end meets following formula (2).

[mathematical expression 2]

0.02 \leq \frac{L 1 - L 2}{L 1} \leq 0.15 - - - (1)

0.02 \leq \frac{S 1 - S 2}{S 1} \leq 0.15 - - - (2)

The relation shown in formula (1) and (2) is met by the width of the conveyance speed and polyester film that make polyester film, become the absolute value of the percent thermal shrinkage in the MD direction of the polyester film made by easily reducing, accompany therewith, the distribution of MD percent thermal shrinkage and the variation of MD percent thermal shrinkage can be reduced.

Wherein, so-called " the width L1 of the polyester film when width of the polyester film in cross directional stretch operation reaches maximum " is the maximum length in the TD direction of polyester film after polyester film is widened along TD direction in extension section.

Shown in Fig. 3, the width L0 of the polyester film 200 before the stretching in preheating part 10 becomes width L1 because utilizing extension section 20 to be widened along TD direction by polyester film 200, in hot wire-CVD portion 40, remove tension force, becomes width L2 when polyester film 200 leaves from cooling end 50.In Fig. 3, become large according to the order width of L0 < L2 < L1.That is, L1 is the maximum width of the polyester film 200 in the cross directional stretch operation of preheating part 10 ~ cooling end 50.

As shown in Figure 3, because the polyester film 200 behind stretched portion 20 is heated, so bandpass L1 also can be called the width (length in TD direction) of the polyester film 200 in thermal finalization portion 30 thereafter in thermal finalization portion 30 under the state applying tension force.

In addition, " the width L2 of the polyester film in the end of the cooling end that polyester film leaves " be arranged in cooling end and the holding component (Fig. 3 be holding component 2j and 2l) holding polyester film leaves polyester film time the width of polyester film.

Because the holding component holding polyester film leaves polyester film, polyester film leaves from the region of cooling end.Such as, the holding component 2j in figure 3 P point, in addition hold component 2l leave polyester film 200 respectively at Q point time, the end (end in MD direction) of cooling end 50 is represented by the straight line of link P point and Q point.

" the conveyance speed S1 of the polyester film in preheating part " is equivalent to hold polyester film and the translational speed of the holding component of edge movement along annular orbit (being 2a ~ 2d in Fig. 3).

In addition, " the conveyance speed S2 of the polyester film in the above-mentioned end of cooling end " be arranged in cooling end and the holding component (Fig. 3 be holding component 2j and 2l) holding polyester film leaves polyester film time the conveyance speed of polyester film.Utilize Fig. 3, if in other words, then such as hold component 2j P point, in addition hold component 2l leave polyester film 200 respectively at Q point time, " the conveyance speed S2 of the polyester film 200 in the above-mentioned end of cooling end 50 " is equivalent to conveyance speed when polyester film 200 exceedes the straight line of link P point and Q point.If further in other words, " the conveyance speed S2 of the polyester film 200 in the above-mentioned end of cooling end 50 " is equivalent to hold the translational speed that component 2j and 2l is about to holding component 2j and 2l before leaving polyester film 200.

Formula (1) means after being stretched by polyester film 200, and when relaxing along TD direction, the mode of preferably shrinking 2% ~ 15% according to maximum width (length in the TD direction) L1 of polyester film 200 in cooling end 50 relaxes.

Formula (2) means when being relaxed along MD direction by polyester film 200, preferably according to the conveyance speed S1 in the preheating part 10 of polyester film 200 slow down in cooling end 50 2% ~ 15% mode relax.

By cross directional stretch operation is set to above-mentioned formation, become the muscle shape protuberance easily suppressing polyester film.

[mathematical expression 3]

\frac{L 1 - L 2}{L 1} \times 100 = ΔL

\frac{S 1 - S 2}{S 1} \times 100 = ΔS

The relaxation rate in the TD direction (transverse direction) of polyester film is represented, so be also called " TD relaxation rate " by Δ L due to Δ L.In addition, the relaxation rate in the MD direction (longitudinal direction) of polyester film is represented due to Δ S, so be also called " MD relaxation rate " by Δ S.

Shown in (1) and (2), Δ L and Δ S is all preferably 2% ~ 15% (2%≤Δ L≤15%, 2%≤Δ S≤15%).

By making Δ L and Δ S be more than 2%, manufactured thinner polyester film becomes and easily meets formula (I) and (II), becomes and easily suppresses muscle shape protuberance.By making Δ L and Δ S be less than 15%, polyester film easily shrinks in stretching device, can suppress lax.

Δ L is more preferably 2% ~ 10% (2%≤Δ L≤10%), more preferably 3% ~ 8% (3%≤Δ L≤8%).In addition, Δ S is more preferably 2% ~ 10% (2%≤Δ S≤10%), more preferably 3% ~ 8% (3%≤Δ S≤8%).

The purposes > of < polyester film

Polyester film of the present invention and thickness reach less than 100 μm thinner film have nothing to do, even if also not easily produced muscle shape by heating conveyance to swell, even if paste coating fluid or functional component sheet material etc. on film, bubble when also not easily producing crawling, sheet material laminating such as to be mixed at the fault.Therefore, may be used for carrying out heating in conveyance and processing or the various uses that is shaped.

Such as can be suitable for optical film, electric insulation film.

In addition, also the film of polyester film of the present invention as solar module can be used.In this case, as long as solar module is such as formed as follows.

Solar module generally configures and converts the luminous energy of sunshine the solar cell device of electric energy to and form between the substrate of the transparency of sunshine incidence and already described polyester film of the present invention (backboard used for solar batteries).As concrete embodiment, also can be configured to under type: by sealant sealings such as generating element (solar cell device) ethylene vinyl acetate copolymer system (EVA system) resins that connects of lead-in wire (not shown) to take out electricity, and be sandwiched between the transparency carriers such as glass and polyester film of the present invention (backboard) and also paste each other and form.

As the example of solar cell device, the various known solar cell devices such as iii-v or II-VI group compound semiconductor system such as the silicon systems such as monocrystalline silicon, polysilicon, amorphous silicon, copper-indium-gallium-selenium, copper-indium-selenium, cadmium-tellurium, gallium-arsenic can be applied.Can form with the resins such as such as ethylene-vinyl acetate copolymer (so-called encapsulant) sealing between substrate and polyester film.

Embodiment

Below, by embodiment, the present invention is more specifically described, but the present invention only otherwise exceed its purport, is not limited to following embodiment.In addition, unless otherwise specified, " part " is quality criteria.

The synthesis > of < polyester feed stock resin

(polyester feed stock resin 1)

As shown below, adopt and terephthalic acid (TPA) and ethylene glycol are directly reacted and water distillation is removed, after carrying out esterification, under reduced pressure carry out the direct esterification of polycondensation, utilize continuous polymerization unit to obtain polyester (Ti catalyst system PET).

(1) esterification

In the first esterification groove, high purity terephthalic acid 4.7 tons and ethylene glycol 1.8 tons of use mixed for 90 minutes and forms slurry, being supplied to continuously in the first esterification groove with the flow of 3800kg/h.Supply the ethylene glycol solution of the citric acid Ti chelator complex compound (VERTECAC-420, JohnsonMatthey Inc.) of citric acid and Ti metal-complexing further continuously, in reactive tank under temperature 250 DEG C, stirring, within about 4.3 hours, react with mean residence time.Now, the mode that citric acid Ti chelator complex compound reaches 9ppm according to Ti addition in element scaled value is added continuously.Now, the acid number of the oligomer obtained is 600 equivalents/ton.In addition, in this description, " equivalent/t " represents the molar equivalent of every 1 ton.

This product is transplanted in the second esterification groove, under agitation, in reactive tank at temperature 250 DEG C, in mean residence time reaction 1.2 hours, obtains the oligomer that acid number is 200 equivalents/ton.The interior separation of the second esterification groove becomes 3 regions, supply the ethylene glycol solution of magnesium acetate from the 2nd region according to Mg addition in the mode that element scaled value reaches 75ppm continuously, then supply the ethylene glycol solution of trimethyl phosphate from the 3rd region according to P addition in the mode that element scaled value reaches 65ppm continuously.

(2) polycondensation reaction

Esterification reaction product obtained above is supplied to continuously in the first polycondensation reaction groove, under agitation, pressure 20torr (2.67 × 10 in reaction temperature 270 DEG C, reactive tank ^-3mPa), under, within about 1.8 hours, its polycondensation is made with mean residence time.

And then, be transplanted in the second polycondensation reaction groove, in this reactive tank, under agitation, pressure 5torr (6.67 × 10 in temperature 276 DEG C, reactive tank in reactive tank ^-4mPa) under, the condition of about 1.2 hours holdup times makes it react (polycondensation).

Then, be transplanted in the 3rd polycondensation reaction groove further, in this reactive tank, pressure 1.5torr (2.0 × 10 in temperature 278 DEG C, reactive tank in reactive tank ^-4mPa), make it react (polycondensation) under the condition of 1.5 hours holdup times, obtain product (PETG (PET)).

Then, obtained product is ejected in cold water with strand shape, cuts immediately and make the particle < cross section of polyester: major diameter is about 4mm, minor axis is about 2mm, length: be about 3mm>.

For obtained polyester, high-resolution type high-frequency inductive coupling plasma weight is used to analyze (HR-ICP-MS; SIINanotechnologyInc. AttoM processed) measuring like that as shown below, result Ti=9ppm, Mg=75ppm, P=60ppm.P reduces slightly relative to addition originally, and presumption produces volatilization in the course of the polymerization process.

The polymer obtained is IV=0.67, amount (the AV)=23 equivalents/ton of terminal carboxyl group, fusing point=257 DEG C, solution mist degree=0.3%.The mensuration of IV and AV is undertaken by method shown below.

The mensuration of ~ IV and AV ~

About the inherent viscosity (IV) of polyester feed stock resin, polyester feed stock resin is dissolved in 1,1,2,2-tetrachloroethanes/phenol (=2/3 [mass ratio]) mixed solvent, is obtained by the solution viscosity at 25 in this mixed solvent DEG C.

End COOH about polyester feed stock resin measures (AV), non-oriented polyester film 1 is dissolved into completely benzyl alcohol/chloroform (=2/3; Volume ratio) mixed solution in, use phenol red as indicator, carry out titration with titer (0.025NKOH-methyl alcohol mixed solution), calculated by its titer.

Operate as described above, synthesized polyester feed stock resin 1.

(polyester feed stock resin 2)

By batch process, solid phase is implemented to polyester feed stock resin 1.That is, the particle of polyester is dropped into after in container, while be set as vacuum and stir, while carry out Pre-crystallizing process at 150 DEG C, at 190 DEG C, carry out the solid-phase polymerization of 30 hours afterwards.

Operate as described above, synthesized polyester feed stock resin 2.

(polyester feed stock resin 3)

Using as 2 of binary acid, 6-naphthalene dicarboxylic acids dimethyl ester 97.6 parts (100 % by mole) and put in ester exchange groove as the ethylene glycol 49.6 parts (100 % by mole) of dihydroxylic alcohols, it is made to heat up while ester exchange reaction limit is carried out in methyl alcohol distillation removing, when methyl alcohol distillates to theoretical amount, product is transferred in polycondensation groove, add as after the germanium oxide 0.016 part of polycondensation catalyst, while be decompressed to high vacuum limit be heated to 290 DEG C and by ethylene glycol distillation removing.Terminate reaction when stirring moment of torsion and just having reached desired value, obtained polymer is taken out with the strand shape of diameter 2.5mm in water.The polymer slicer of obtained strand shape is cut into flake.The inherent viscosity (IV) of the polymer obtained is 0.60.

Operate as described above, obtain the polyester feed stock resin 3 of poly-NDA glycol ester (PEN).

(polyester feed stock resin 4)

With reference to the paragraph [0107] (embodiment 1) of Japanese Unexamined Patent Publication 2009-149066 publication, prepare polyester feed stock resin 4.

(embodiment 1)

The making > of the non-oriented polyester film of <

-film forming process-

Polyester feed stock resin 1 being dried to moisture content is after below 20ppm, and putting into diameter is in the hopper of single shaft mixing extruder of 50mm.Polyester feed stock resin 1 melting at 300 DEG C, by following extrusion condition, via gear pump, filter (aperture is 20 μm), extrudes from mould.In addition, the mode reaching 0.6mm according to the thickness of polyester sheet adjusts the size of the slit of mould.The thickness of polyester sheet is measured by the automatic thickness meter of the outlet being arranged at curtain coating drum.

Now, molten resin extrude be set to 1% in pressure oscillation, the Temperature Distribution of molten resin carries out under being set to the condition of 2%.Specifically, the back pressure in the cylinder of extruder is set to the pressure of average pressure high 1% in the cylinder relative to extruder, the pipe arrangement temperature of extruder is set to the temperature of mean temperature high 2% in the cylinder relative to extruder and heats.When extruding from mould, molten resin being expressed on the curtain coating drum of cooling, utilizing electrostatic to apply method and adhering on curtain coating drum.About the cooling of molten resin, the temperature that curtain coating is bulging is set as 25 DEG C, blows and fuses melt resin from blowing out the cold wind of 25 DEG C with the bulging cold wind generator be oppositely arranged of curtain coating simultaneously.Utilize and the angle stripper that be oppositely disposed of curtain coating drum, be 0.6mm by thickness from curtain coating drum, non-oriented polyester film (non-oriented polyester film 1) stripping that film width is 0.9m.

The inherent viscosity IV=0.64dL/g of the non-oriented polyester film 1 obtained, amount (the AV)=25 equivalents/ton of terminal carboxyl group, glass transition temperature (Tg)=72 DEG C.

The mensuration of ~ IV and AV ~

About the inherent viscosity (IV) of non-oriented polyester film, non-oriented polyester film is dissolved in 1,1,2,2-tetrachloroethanes/phenol (=2/3 [mass ratio]) mixed solvent, is obtained by the solution viscosity at 25 in this mixed solvent DEG C.

End COOH about non-oriented polyester film measures (AV), non-oriented polyester film is dissolved into completely benzyl alcohol/chloroform (=2/3; Volume ratio) mixed solution in, use phenol red as indicator, carry out titration with titer (0.025NKOH-methyl alcohol mixed solution), calculated by its titer.

The making > of < biaxially oriented polyester film

For obtained non-oriented polyester film 1, stretching by being undertaken successively biaxial stretch-formed by following method, making the biaxially oriented polyester film 1 that thickness is 50 μm, film width (total length in TD direction) is 2.5m.

-longitudinal stretching operation-

Passed through between 2 pairs of different niprolls of peripheral speed by non-oriented polyester film 1, under the following conditions longitudinally (conveyance direction) stretches.

Preheat temperature: 80 DEG C

Longitudinal drawing temperature: 90 DEG C

Longitudinal stretching multiplying power: 3.5 times

Longitudinal stretching stress: 12MPa

-cross directional stretch operation-

For the polyester film 1 (longitudinal stretching polyester film 1) through longitudinal stretching, use the stenter (biaxial stretcher) with the structure shown in Fig. 3, stretch with following method, condition.

(preheating part)

Preheat temperature is set to 110 DEG C, heats to make it possible to stretch.

(extension section)

Film width (TD direction) vertical along the direction (length direction) with longitudinal stretching for longitudinal stretching polyester film 1 after preheating is applied tension force under following condition, carries out cross directional stretch.

< condition >

Draft temperature (transverse drawing temperature): 125 DEG C

Stretching ratio (cross directional stretch multiplying power): 4.2 times

Tensile stress (lateral tensile stress): 18MPa

(thermal finalization portion)

Then, being up to of polyester film is reached film surface temperature (heat setting temperature) and control to heat in following ranges, makes its crystallization.

Be up to and reach film surface temperature (heat setting temperature T _{thermal finalization}): 220 (DEG C)

Heat setting temperature T wherein _{thermal finalization}for the pre-peak temperature (DEG C) of DSC.

In addition, radiation heating is carried out to the infrared heater (heater surface temperatures: 650 DEG C) that the both ends of film width (TD direction) are made by pottery by the side, curtain coating face contacted with curtain coating drum in film forming process.Now, the distance of heater and polyester film is set to 170mm.

(hot wire-CVD portion)

Polyester film after thermal finalization is heated to following temperature, by the tension recovery of film.Now, by infrared heater (heater surface temperatures: 350 DEG C), radiation heating is carried out by side, curtain coating face to the both ends of film width in the same manner as thermal finalization.

Hot wire-CVD temperature (T _{hot wire-CVD}): 150 DEG C

Hot wire-CVD rate: TD direction (TD hot wire-CVD rate; Δ L)=5%

MD direction (MD hot wire-CVD rate; Δ S)=5%

(cooling end)

Then, the polyester film after hot wire-CVD is cooled under the chilling temperature of 65 DEG C.

Now, average cooling rate is set to 40 DEG C/sec, the multiplying power relative to the average cooling rate in the central portion of film TD direction (being expressed as in specific circulating ratio, table 1 " end/central portion ") of the average cooling rate in film width end is set to 1.1 times.

-recovery of film-

After cooling is complete, every for the two ends of polyester film 20cm is pruned.Afterwards, after two ends carry out extruding processing (embossing) with width 10mm, batch with tension force 25kg/m.

Operate as described above, made the biaxially oriented polyester film (PET film) that thickness is 50 μm.

-A. evaluation of measuring-

Following mensuration, evaluation are carried out to the biaxially oriented polyester film of above-mentioned making.The result measure, evaluated is shown in following table 1.

(1) the MD percent thermal shrinkage on TD direction and MD percent thermal shrinkage inequality

Biaxially oriented polyester film is cut, makes the coupons M of the size of 30mm, MD direction, TD direction 120mm.For coupons M, according to the mode at interval reaching 100mm in the MD direction, draw 2 foundation directrixes, place 30 minutes in the heated oven of 150 DEG C under no-station pole canopy.After this placement, coupons M is cooled to room temperature, measures the interval of 2 foundation directrixes, this value is set to A (unit; Mm).Numerical value formula by measured A and " 100 × (100-A)/100 " calculated is as MD percent thermal shrinkage (Sh).

To the end from TD direction of film to another end, every 50mm (the 50mm interval, central point interval in the TD direction of each coupons M) measures described MD percent thermal shrinkage, calculates the maximum numerical value of MD percent thermal shrinkage and the difference of minimum numerical value as MD percent thermal shrinkage deviation (Δ Sh).In addition, will represent that the schematic diagram of the method measuring MD percent thermal shrinkage is shown in Figure 4.

(2) the maximum Y [%/m of the maximum X [%/m] of MD percent thermal shrinkage variable quantity x [%/m] absolute value of the per unit distance in film TD direction and the rate of change y absolute value of the per unit distance of x ²] mensuration

X measures MD percent thermal shrinkage (150 DEG C and 30 minutes) to biaxially oriented polyester film every 0.05m on TD direction, is calculated by following formula.

X=(the MD thermal contraction rate variance adjacent in arbitrary position) ÷ 0.05m

In addition, x also can get negative value.

Maximum on the width that X is calculated x absolute value.

Y due to the rate of change of the per unit distance for x, so calculated by following formula.

Y=(difference of the x between the measuring point that arbitrary position adjoins) ÷ 0.05m

In addition, y also can get negative value.

Y is the maximum on the width of y absolute value.

(3) mensuration of thickness

The thickness of the biaxially oriented polyester film obtained is tried to achieve as follows.

For biaxially oriented polyester film, use contact determining film thickness meter (ANRITSU Inc.), on the direction (length direction) of longitudinal stretching to whole 0.5m with periodic sampling 50 point, further on film width (direction vertical with length direction) to film overall with after (in the width direction 50 deciles) sample at 50 at equal intervals, measure this thickness of 100.Obtain this average thickness of 100, as the thickness of polyester film.

(4) the pre-peak temperature deviation of DSC (Δ Tpp)

For obtained biaxially oriented polyester film, to the overall with from an end in TD direction to another end of film, sample 11 points equably, measure the pre-peak temperature of DSC (Tpp).Using the difference (Δ Tpp) of the maxima and minima of measured multiple Tpp values as the pre-peak temperature deviation of DSC.

In addition, the pre-peak temperature of DSC is that the film of sampled coupons is placed ormal weight (2 ~ 10mg) in the DSC-60 of Shimadzu Scisakusho Ltd, is warming up to 300 DEG C carries out measuring with the programming rate of 10 DEG C/min.Read in the peak temperature of the endothermic peak occurred in front of the melting hump of polyester (PET) as the pre-peak temperature of DSC (Tpp).

(5) muscle shape protuberance judges

For obtained biaxially oriented polyester film, the degree of being swelled by the muscle shape of visualization face, is evaluated according to following metewand.

< metewand >

AA: the generation substantially not seeing muscle shape protuberance.

A: the generation seeing muscle shape protuberance a little, but face is good.

B: the generation seeing muscle shape protuberance, but for practicality there is no the degree of obstacle.

C: the generation significantly seeing muscle shape protuberance.

(embodiment 2 ~ embodiment 9 and comparative example 1 ~ comparative example 4)

In embodiment 1, except the condition shown in list of modification 1, all similarly operate, obtain the biaxially oriented polyester film of embodiment 2 ~ embodiment 9 and comparative example 1 ~ comparative example 4.

In addition, for obtained biaxially oriented polyester film, by the method same with the biaxially oriented polyester film of embodiment 1, the evaluation of physical property and the muscle shape protuberance that carry out biaxially oriented polyester film are evaluated.Show the result in table 1.

(comparative example 5)

According to the embodiment 1 of Japanese Unexamined Patent Publication 2009-149066 publication, obtain biaxially oriented polyester film.

For obtained biaxially oriented polyester film, by the method same with the biaxially oriented polyester film of embodiment 1, the evaluation of physical property and the muscle shape protuberance that carry out biaxially oriented polyester film are evaluated.Show the result in table 1.

[table 1]

As shown in table 1, in embodiment, with the contrast of comparative example, less inhibit the generation that muscle shape swells.

Its entirety of disclosure of the Japanese patent application 2013-069479 of application on March 28th, 2013 is by referring to being included in this description.The whole documents recorded in this description, patent application and technical standard and specifically and record each document, patent application and technical standard respectively by referring to situation about including in same extent by referring to including in this description.About illustrative embodiment of the present invention above record for illustrate and illustrate object carry out, be not intended to enlist the services of or be defined in open invention mode itself.Obviously, many changes or change are self-evident for those skilled in the art.Above-mentioned embodiment illustrates the principle of invention and the application of practicality best, is invent in order to other those skilled in the art can understand and select, record together with the various embodiment such with being suitable for imaginary specific purposes or various change.Be intended that scope of the present invention and be subject to following claim and the regulation of equipollent thereof.

Symbol description

2a ~ 2l ... hold component

10 ... preheating part

20 ... extension section

30 ... thermal finalization portion

40 ... hot wire-CVD portion

50 ... cooling end

60 ... annular orbit

100 ... biaxial stretcher

200 ... polyester film

Claims

1. a polyester film, its thickness is less than 100 μm,

Following maximum X and maximum Y meets following formula (I) and (II),

Described maximum X be film width, described film width per unit distance with the maximum X [%/m] of percent thermal shrinkage variable quantity x [%/m] absolute value of described film width vertical direction,

Described maximum Y is the maximum Y [%/m of the rate of change y absolute value relative to film width per unit distance of described x ²],

0.01＜X＜2.00…(I)

0.1＜Y＜20.0…(II)。

2. polyester film according to claim 1, wherein,

Described film width central portion be more than 0.01% with the percent thermal shrinkage of described film width vertical direction and less than 3%.

3. polyester film according to claim 1 and 2, wherein,

Described film width be more than 0.01% with the percent thermal shrinkage deviation of described film width vertical direction and less than 0.5%.

4. the polyester film according to any one of claims 1 to 3, wherein,

Be more than 0.5 DEG C and less than 10 DEG C in the pre-peak temperature deviation measured by means of differential scanning calorimetry mensuration and DSC of described film width.

5. the polyester film according to any one of Claims 1 to 4, wherein,

The inherent viscosity of polyester film is more than 0.55dL/g and below 0.90dL/g.

6. the polyester film according to any one of Claims 1 to 5, wherein,

The amount of the terminal carboxyl group of polyester film is more than 5eq/ ton and below 35eq/ ton.

7. the polyester film according to any one of claim 1 ~ 6, wherein,

From 3 officials can above polyfunctional monomer Component units be more than 0.005 % by mole and less than 2.5 % by mole containing ratio relative to whole Component units of the polyester in polyester film.

8. a manufacture method for polyester film, it comprises:

Film forming process, melt extrudes slabbing by polyester feed stock resin, and cooling on curtain coating drum, makes polyester film be shaped;

Longitudinal stretching operation, carries out longitudinal stretching along its length by the described polyester film after being shaped; And

Cross directional stretch operation, described polyester film is transported to following portion successively, polyester film after described longitudinal stretching is carried out cross directional stretch along the width vertical with described length direction, and wherein said each portion is: the preheating part polyester film after described longitudinal stretching being preheated to the temperature that can stretch; Described polyester film after preheating is applied tension force along the width vertical with described length direction and carries out the extension section of cross directional stretch; The thermal finalization portion making its crystallization and thermal finalization is heated to the described polyester film after carrying out described longitudinal stretching and described cross directional stretch; Polyester film after described thermal finalization is heated, by the tension recovery of polyester film to the hot wire-CVD portion of overstrain except striping; And by the cooling end of the polyester film cooling after hot wire-CVD,

In at least one in described thermal finalization portion and described hot wire-CVD portion, heater is utilized to carry out selective radiation heating to the end of the polyester film of described width, and, in described cooling end, the average cooling rate of film width end when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to 1.01 times ~ 2 times of the average cooling rate of the central portion of film width.

9. the manufacture method of polyester film according to claim 8, wherein,

Described radiation heating utilizes pottery heater processed to carry out.

10. the manufacture method of polyester film according to claim 8 or claim 9, wherein,

The width L2 of the described polyester film of the end of the described cooling end when width L1 of described polyester film and described polyester film leave from described cooling end when the width of polyester film reaches maximum described in described cross directional stretch operation meets following formula (1), and,

Described in the conveyance speed S1 of polyester film described in described preheating part and the described end of described cooling end, the conveyance speed S2 of polyester film meets following formula (2),

0.02 \leq \frac{L 1 - L 2}{L 1} \leq 0.15 - - - (1)

0.02 \leq \frac{S 1 - S 2}{S 1} \leq 0.15 - - - (2) .

The manufacture method of the polyester film according to any one of 11. according to Claim 8 ~ 10, wherein,

Described cross directional stretch operation uses the biaxial stretch-formed device of the following stated, this biaxial stretch-formed device has described preheating part, described extension section, described thermal finalization portion, described hot wire-CVD portion and described cooling end, and use at least two holding components to hold the both ends of the width of described polyester film at described preheating part for an end, by described polyester film from described preheating part conveyance to described cooling end

By with hold in described preheating part a described polyester film width end described holding component and be adjacent to this holding component holding component interval compared with, hold the interval between the described holding component of a described polyester film width end and the holding component being adjacent to this holding component in cooling end described in constriction, thus reduce the conveyance speed of described polyester film.

The manufacture method of the polyester film according to any one of 12. according to Claim 8 ~ 11, wherein,

In described cooling end, average cooling rate when being cooled to 70 DEG C by making the surface temperature of polyester film from 150 DEG C is set to the scope of 2 DEG C/sec ~ 100 DEG C/sec.