CN107406604A

CN107406604A - Stretch white polyester film and its manufacture method, backboard used for solar batteries and solar module

Info

Publication number: CN107406604A
Application number: CN201680016333.0A
Authority: CN
Inventors: 浜田保弘
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2015-03-31
Filing date: 2016-03-14
Publication date: 2017-11-28
Anticipated expiration: 2036-03-14
Also published as: CN107406604B; KR20170118187A; JP6348867B2; KR102124240B1; WO2016158357A1; JP2016194009A

Abstract

The present invention provides a kind of stretching white polyester film and its application, the stretching white polyester film contains polyester and white particles, white particles are 2~10 mass % relative to the content of total film mass, and the average area on the section in film thickness direction with every 1 is 0.010~0.050 μm²/ hole.The manufacture method of stretching white polyester film has：By longitudinal stretching process that non-stretched white polyester film is stretched along its length and the 1st~the N cross directional stretch processes stretched in the width direction, compared with the n-th 1 cross directional stretch processes, increase the draw speed of white polyester film in the direction of the width in the n-th cross directional stretch process, in N cross directional stretch processes, draft temperature is set to 140~180 DEG C, and the length of the width of the white polyester film before starting relative to the 1st stretching process, the length of width is increased into by 8~25%/second.N is more than 2 integer, and n is 2~N integer.

Description

Stretch white polyester film and its manufacture method, backboard used for solar batteries and too Positive energy battery module

Technical field

The present invention relates to one kind stretching white polyester film and its manufacture method, backboard used for solar batteries and solar energy Battery module.

Background technology

In recent years, from the viewpoint of environment of preserving our planet, the solar power generation that sunshine is converted to electricity gets most of the attention. Solar module for solar power generation has is sequentially laminated with sealant/sun on the incident glass of sunshine The structure of energy cell device/sealant/back protection film.

Solar module need to possess higher weather resistance, so as to exposed to the harsh of wind and rain and direct sunlight Under use environment, the battery performances such as generating efficiency can be also kept between the longer-term as decades.It is this resistance in order to assign Performance is waited, the back protection film for forming solar module (below, is sometimes referred to as " backboard used for solar batteries " or " back of the body Plate ".) and many materials such as encapsulant of potted component be also required to weatherability.

Typically using resin materials such as polyester in backboard used for solar batteries.Generally exist on the surface of polyester film more Carboxyl and hydroxyl, hydrolysis is easily caused in the environment of it moisture be present, have because through when the tendency that deteriorates.Therefore, for putting Require to suppress in the outdoor polyester film waited all the time used in the solar module under the such environment of wind and rain Its is water-disintegrable.

Also, the light of encapsulant has been transmitted by the back of the body used for solar batteries in order to not absorbed by solar cell device Plate reflects and improves generating efficiency, proposes the white backboard for having using with the addition of the white particles such as titanium oxide.

For example, have sealing rear surface of solar cell polyester film disclosed in International Publication No. 12/008488, its wavelength 550nm light reflectivity is more than 50%, the inorganic particles such as titanium oxide containing 3~50 mass %, the acid number of film for 1~ 30eq/ton, the inherent viscosity of film is 0.60~0.80dL/g.

Also, there are the polyester film with polyester layer, the polyester disclosed in Japanese Unexamined Patent Publication 2014-25052 publications Film contains relative to the particulate of titanium oxide that polyester is 0.1~10 mass %, 0.1~10 mass % end-capping reagent etc., in particulate Around there is hole, be present in the long side of orthogonal projection of the hole around 1 particulate in film profile remove with it is micro- Line segment (Lb) and orthogonal projection of 1 particulate in film profile obtained from the part that orthogonal projection of the grain in film profile repeats The average value of the ratio between long side (Lp) (Lb/Lp) be 0.5~2.

Also, there is white multi-layer polyester film disclosed in Japanese Unexamined Patent Publication 2014-162107 publications, it has borderline region And including across the constant containing ratio region of more than 2 of borderline region and the constant containing ratio region of opposed pairs, frontier district The thickness in domain is 0.15~3 μm, and across borderline region, at least one in the constant containing ratio region of opposed pairs includes oxygen Change particulate or the hole such as titanium, across borderline region and the constant containing ratio region of opposed pairs particulate or hole containing ratio it Difference is 1~30%, and borderline region is included between the containing ratio in borderline region and the constant containing ratio region of opposed pairs Containing ratio particulate or hole.

The content of the invention

The invention technical task to be solved

In order that solar module keeps higher generating efficiency for a long time, wanted as to backboard used for solar batteries The performance asked, weatherability (hydrolytic resistance), cementability (peel resistance) and light reflective with encapsulant can be enumerated.

When there is the backboard of light reflective using polyester manufacture, it is however generally that, in order to improve light reflective, by leucoplastid In sub (titanium oxide etc.) incorporation polyester, in order to improve weatherability, the polyester film for extruding slabbing is stretched.Pass through drawing To stretch, the interface of white particles and polyester is peeling-off and produces space (hole), if but produce a large amount of holes, it is exposed to for a long time When outdoor, thin film strength declines to a great extent, and can produce the cleavage fracture of film, causes to decline with the adhesiveness of encapsulant.

For example, in backboard disclosed in International Publication No. 12/008488, on (resistance to the cementability of encapsulant Fissility) do not take in.

Also, in the backboard disclosed in Japanese Unexamined Patent Publication 2014-25052 publications, on being externally exposed air for a long time When do not taken in the adhesiveness of encapsulant.

Also, it is necessary to which to be laminated void content different in the backboard disclosed in Japanese Unexamined Patent Publication 2014-162107 publications Layer is, it is necessary to import special equipment.

In view of above-mentioned condition of the present invention is excellent its object is to provide a kind of weatherability, light reflective and peel strength The stretching white polyester film and its manufacture method of individual layer and help to realize higher generating efficiency in long-term use Backboard and solar module used for solar batteries.

For solving the means of technical task

To achieve these goals, there is provided following invention.

A kind of stretching white polyester films of the ＞ of ＜ 1, it contains polyester and white particles, and white particles are relative to the total matter of film The content of amount is 2~10 mass %, and the average area on the section in film thickness direction with every 1 is 0.010~0.050 μm²/ hole.

Stretching white polyester films of the ＞ of ＜ 2 according to the ＞ of ＜ 1, wherein, on the section of the thickness direction of film, hole The ratio of the gross area shared by gap is 0.5~3%.

Stretching white polyester films of the ＞ of ＜ 3 according to the ＞ of ＜ 1 or the ＞ of ＜ 2, wherein, when by tearing strength be set to P, will When the thickness of film is set to t, P/t is 6.5~13.5mN/ μm.

P unit is mN, and t unit is μm.

Stretching white polyester films of the ＞ of ＜ 4 according to any one of the ＞ of 1 ＞ of ＜~＜ 3, wherein, the thickness of film is 280~500 μm.

Stretching white polyester films of the ＞ of ＜ 5 according to any one of the ＞ of 1 ＞ of ＜~＜ 4, wherein, the characteristic of film is glued Number is 0.65~0.85dL/g.

Stretching white polyester films of the ＞ of ＜ 6 according to any one of the ＞ of 1 ＞ of ＜~＜ 5, wherein, white particles are oxygen Change titanium.

A kind of backboards used for solar batteries of the ＞ of ＜ 7, the stretching white that it is included any one of the ＞ of 1 ＞ of ＜~＜ 6 are poly- Ester film.

Used for solar batteries backboards of the ＞ of ＜ 8 according to the ＞ of ＜ 7, it is at least one face of stretching white polyester film With coating layer.

A kind of solar modules of the ＞ of ＜ 9, it is included：

Solar cell device；

Encapsulant, seal solar cell device；

Front side substrate, it is configured in the light surface side of solar cell device more more outward than encapsulant；And

According to the backboard used for solar batteries described in the ＞ of ＜ 7 or the ＞ of ＜ 8, in solar cell device and light surface side phase Anti- side is configured at more more outward than encapsulant.

A kind of manufacture methods for stretching white polyester film of the ＞ of ＜ 10, it is any one of 1 ＞ of manufacture ＜~＞ of ＜ 6 Stretching white polyester film method, have：

Extrusion operation, after the mixture melting extrusion containing Starting Material Polyester and white particles, cooled down and be molded Non-stretched white polyester film；And

Enter longitudinal stretching process that non-stretched white polyester film is stretched along its length and in the width direction The cross directional stretch process of row stretching,

Cross directional stretch process has the 1st~the N cross directional stretch processes, and the n-th cross directional stretch process continues the (n-1)th cross directional stretch Process and carry out, compared with the (n-1)th cross directional stretch process, in the n-th cross directional stretch process increase white polyester film in width Draw speed on direction, in N cross directional stretch processes, draft temperature is set to 140~180 DEG C, and be set to relative to the 1st Cross directional stretch process start before white polyester film width length increase by 8~25%/second width length Draw speed.

N is more than 2 integer, and n is 2~N integer.

The manufacture method of stretching white polyester films of the ＞ of ＜ 11 according to the ＞ of ＜ 10, wherein, the 1st cross directional stretch process Draw speed in the direction of the width be 4~10%/second.

The manufacture method of stretching white polyester films of the ＞ of ＜ 12 according to the ＞ of ＜ 10 or the ＞ of ＜ 11, wherein, when by the 1st The draw speed in the direction of the width of cross directional stretch process be set to Sa, by N cross directional stretch processes in the direction of the width When draw speed is set to Sb, value of the draw speed than Sb/Sa is 1.5~6.

Invention effect

In accordance with the invention it is possible to provide the stretching white of a kind of weatherability, light reflective and the excellent individual layer of peel resistance Polyester film and its manufacture method and help to realize the back of the body used for solar batteries of higher generating efficiency in long-term use Plate and solar module.

Brief description of the drawings

Fig. 1 is the general of one of the biaxial stretcher used in the manufacture for the stretching white polyester film for representing the disclosure Sketch map.

Fig. 2 is to represent that the white in the manufacturing process of the stretching white polyester film of the disclosure in cross directional stretch process is gathered The skeleton diagram of one of the stretching mode of ester film.

Embodiment

Hereinafter, embodiments of the present invention are illustrated, but implementation below is one of the present invention, and the present invention is simultaneously It is not limited to implementation below.

In addition, in present specification, "~" that represents number range be using by its front and rear described numerical value under Limit value and higher limit and comprising implication use.Also, when only higher limit records unit in number range, represent Lower limit is also and higher limit identical unit.

[stretching white polyester film]

The disclosure stretching white polyester film (it is following, be designated as sometimes " white polyester film ", " polyester film " or " thin Film ".) containing polyester and white particles, white particles are 2~10 mass % relative to the content of total film mass, thick in film The average area on the section in degree direction with every 1 is 0.010~0.050 μm²/ hole.

The weatherability, reflectivity and peel resistance that stretch white polyester film of the disclosure are excellent.Its reason is presumed as follows.

Think in the oriented polyester film of white particles is mixed with, especially by " stretching " for assigning weatherability And caused hole causes thin film strength to decline.The result of research is repeated in the present inventor, finds as follows：If hole mistake Small, i.e. explanation stretching is insufficient, can not assign sufficient weatherability, if on the contrary, excessive, when being externally exposed air for a long time, Moisture easily immerses in hole and promotes hydrolysis, easily produces the cleavage fracture of film.

In contrast, the content that the stretching white polyester film of the disclosure passes through white particles is more than 2 mass %, can Obtain higher light reflective, and by the way that for below 10 mass %, higher intensity can be kept.

And, it is believed that the hole in the presence of the stretching white polyester film of the disclosure passes through cuing open in film thickness direction The average area of every 1 is 0.010 μm on face²/ more than and be stretched sufficiently, so as to having higher weatherability, the opposing party Face, by for 0.050 μm²/ below, the cleavage in film being not in most larger spaces and being difficult to produce film is broken Split.Therefore, even if being externally exposed for a long time in air, it is not easy to down with the cementability (peel resistance) of other layers such as encapsulant Drop.

In addition, the result of research is repeated in the present inventor, by be mixed with white particles Starting Material Polyester melting extrusion and Formed after non-stretched white polyester film when being stretched and manufacturing stretching white polyester film, by by stretching condition control Making in proper range, can control the size for the hole being formed in film, so as to simply manufacture the individual layer of the disclosure Stretching white polyester film.

(polyester)

The species of contained polyester is not particularly limited in the stretching white polyester film of the disclosure, can be used known Polyester.

For example, it can enumerate by aromatic acid or its ester formative derivative and glycol or its ester formative derivative The wire saturated polyester of synthesis.As the concrete example of wire saturated polyester, PET, poly- isophthalic can be enumerated Dioctyl phthalate second diester, polybutylene terephthalate, polycyclohexane terephthalate, poly- 2,6- naphthalenedicarboxylic acids second Diester etc..Wherein, from the viewpoint of the balance of mechanics physical property and cost, particularly preferred PET, poly- 2, 6- polyethylene naphthalates, polycyclohexane terephthalate etc..

Polyester can be homopolymer or copolymer.In addition, in the white polyester film of the disclosure, as resin Composition, it can contain and be mixed with a small amount of resin of the other kinds of resin such as polyimides in the polyester.

The species of polyester is not limited to above-mentioned polyester, can also use other polyester.For example, it may be use dicarboxylic acids Composition and diol component can also use commercially available polyester come the polyester synthesized.

When synthesizing polyester, such as enter by using known method (a) dicarboxylic acid component and (b) diol component At least one of row esterification and ester exchange reaction are reacted and obtained.

As (a) dicarboxylic acid component, such as malonic acid, butanedioic acid, glutaric acid, adipic acid, suberic acid, the last of the ten Heavenly stems two can be enumerated The aliphatic such as acid, dodecanedioic acid, dimeric dibasic acid, eicosane diacid, pimelic acid, azalaic acid, methylmalonic acid, ethyl malonic acid Omega-dicarboxylic acids；The alicyclic dicarboxylic acids such as adamantane dicarboxylic acids, norbornene dicarboxylic acids, cyclohexane dicarboxylic acid, naphthalane dicarboxylic acids；It is right Phthalic acid, M-phthalic acid, phthalic acid, 1,4- naphthalene dicarboxylic acids, 1,5- naphthalene dicarboxylic acids, 2,6 naphthalene dicarboxylic acid, 1,8- naphthalenes Dicarboxylic acids, 4,4 '-diphenyldicarboxylic acid, 4,4 '-diphenyl ether dicarboxylic acids, 5-sodium sulfo isophthalate, phenyl indan dicarboxyl The aromatic dicarboxylic acid such as acid, anthracene dicarboxylic acids, luxuriant and rich with fragrance dicarboxylic acids, 9,9 '-bis- (4- carboxyl phenyls) fluorenic acids；Derive Deng dicarboxylic acids or its ester Thing.

As (b) diol component, for example, can enumerate ethylene glycol, 1,2-PD, 1,3-PD, BDO, The aliphatic diol class such as 1,2- butanediols, 1,3 butylene glycol；The ester ring types such as cyclohexanedimethanol, the spiroglycol, isobide two Alcohols；The aromatic diol class such as bisphenol-A, 1,3- benzene dimethanols, 1,4- benzene dimethanols, 9,9 '-bis- (4- hydroxy phenyls) fluorenes；Deng two Alcoholic compound.

As (a) dicarboxylic acid component, preferably using at least one kind of in aromatic dicarboxylic acid.Further preferably dicarboxylic acids into Aromatic dicarboxylic acid in point is as principal component.Here, " principal component " refers to that aromatic dicarboxylic acid is shared in dicarboxylic acid component Ratio be more than 80 mass %.The dicarboxylic acid component in addition to aromatic dicarboxylic acid can also be contained.As this dicarboxylic acids Composition, it is ester derivants such as aromatic dicarboxylic acid etc..

As (b) diol component, preferably using at least one kind of in aliphatic diol.As aliphatic diol, such as can Containing ethylene glycol, ethylene glycol is preferably comprised as principal component.Here, principal component refers to ethylene glycol ratio shared in diol component Example is more than 80 mass %.

The usage amount of aliphatic diol (such as ethylene glycol) is relative to aromatic dicarboxylic acid (such as terephthalic acid (TPA)) and root According to 1 mole of its ester derivant of needs, preferably 1.015~1.50 moles of scope.The usage amount of aliphatic diol is more excellent Elect the scope of 1.02~1.30 moles of scope, more preferably 1.025~1.10 moles as.If the use of aliphatic diol The scope for more than 1.015 moles is measured, then esterification can be carried out well, if the scope below 1.50 moles, then can be pressed down System, can be by fusing point, glass transition temperature, crystallization for example as the accessory substance of the diethylene glycol caused by the dimerization of ethylene glycol Property, many characteristics such as heat resistance, hydrolytic resistance, weatherability remain well.

Known catalysts can be used in esterification or ester exchange reaction.As catalysts, Ke Yiju Go out alkali metal compound, alkaline earth metal compound, zinc compound, lead compound, manganese compound, cobalt compound, aluminium compound, antimony Compound, titanium compound, phosphorus compound etc..Any stage generally preferably before the manufacture of polyester is completed adds antimony chemical combination Thing, germanium compound, titanium compound etc. are used as polymerization catalyst.As this method, if for example using germanium compound as example, it is excellent Germanium compound powder is directly added in choosing.

For example, in esterification process, in the presence of the catalyst containing titanium compound, by aromatic dicarboxylic acid and Aliphatic diol is polymerize.It is titanium compound as catalyst in the esterification, uses using organic acid and be used as part Organic chelated titanium complex, and set in process and at least add organic Ti chelator complex compound, magnesium compound successively and do not have The process for having 5 valency phosphates of the aromatic rings as substituent is preferred.

Specifically, in esterification process, first, before addition magnesium compound and phosphorus compound, by aromatic series Dicarboxylic acids and aliphatic diol are mixed with the catalyst containing the organic chelated titanium complex as titanium compound.Organic chelate Closing the titanium compounds such as titanium complex also has higher catalytic activity to esterification, therefore can carry out being esterified instead well Should.At this point it is possible to titanium compound is added during mixed aromatic dicarboxylic acid component and aliphatic diol composition, can also After mixed aromatic dicarboxylic acid component (or aliphatic diol composition) and titanium compound mixing-in fat race diol component (or virtue Fragrant race dicarboxylic acid component).And it is possible to mixed aromatic dicarboxylic acid component and aliphatic diol composition and titanium compound simultaneously. Mixed method is not particularly limited, can be carried out by known method.

Here, further preferably add following compounds when carrying out the polymerization of above-mentioned polyester.

As the phosphorus compound of 5 valencys, the phosphate of 5 valencys without the aromatic rings as substituent can be used at least It is a kind of.For example, phosphate ((OR) of the low alkyl group as substituent with carbon number below 2 can be enumerated₃- P=O；R The alkyl of=carbon number 1 or 2), specifically, particularly preferred trimethyl phosphate, triethyl phosphate etc..

As the addition of phosphorus compound, preferably P element scaled value turns into the amount of 50ppm~90ppm scope.Phosphatization is closed The amount of thing, which is more preferably P element scaled value, turns into 60ppm~80ppm amount, more preferably as 60ppm~75ppm's Amount.

By containing magnesium compound in the polyester, the electrostatic imposing of polyester is improved.

As magnesium compound, such as the magnesium salts such as magnesia, magnesium hydroxide, magnesium alkoxide, magnesium acetate, magnesium carbonate can be enumerated.Its In, from the viewpoint of the dissolubility to ethylene glycol, most preferably magnesium acetate.

As the addition of magnesium compound, in order to assign higher electrostatic imposing, preferably Mg elements scaled value turns into More than 50ppm amount, more preferably as 50ppm~100ppm scope amount.In the viewpoint for assigning electrostatic imposing, magnesium The addition of compound is preferably amount of the Mg elements scaled value as 60ppm~90ppm scope, is more preferably turned into The amount of 70ppm~80ppm scope.

In esterification process, following relational expressions (ii) are particularly preferably met with the value Z calculated according to following formula (i) Mode add the titanium compound as catalyst component, the magnesium compound as additive and phosphorus compound and make its melting poly- Close.Here, P content is the overall phosphorus amount of the phosphorus compound from the phosphate containing 5 valencys without aromatic rings, Ti contents are Titanium amount from the Ti compound entireties containing organic chelated titanium complex.In this way, by selecting in urging containing titanium compound Magnesium compound and phosphorus compound are used in agent system simultaneously and controls addition moment and adding proportion, maintains moderately high titanizing The catalytic activity of compound, while few tone that turns to be yellow can be obtained, when can assign film when polymerisation or thereafter (during melting) etc. is exposed to the heat resistance for being also difficult to produce yellow coloring under high temperature.

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

(ii)0≤Z≤5.0

Because phosphorus compound acts not only on titanium, but also interacted with magnesium compound, therefore it just turns into quantitatively The index of the balance of performance.

Formula (i) for performance subtracted from the phosphorus total amount that can be reacted act on magnesium it is phosphorus composition, can act on titanium The formula of the amount of phosphorus.In the case where value Z is just, the phosphorus of titanium is hindered to be in superfluous situation, conversely in the case of negative, it may be said that The phosphorus needed for titanium is hindered to be in the situation of deficiency.In the reaction, 1, Ti, Mg, P each atom and non-equivalence, therefore in formula Respective molal quantity is multiplied by valence mumber and implements to weight.

In addition, special synthesis etc. need not be carried out in the synthesis of polyester, and can use cheap and readily available Titanium compound, phosphorus compound and magnesium compound keep reacting required reactivity, while can obtain tone and to heat The excellent polyester of coloring resistance.

In formula (ii), from the sight of the further raising tone in the state of polymerisation reactivity is kept and the coloring resistance to heat Point considers, preferably meets the situation of 1.0≤Z≤4.0, more preferably meets the situation of 1.5≤Z≤3.0.

As the preferred mode of esterification process, mode is preferably as follows：Before esterification terminates, to aromatic series two That 1ppm~30ppm is added in carboxylic acid and aliphatic diol is used as the chelate titanium complex of part using citric acid or citrate It is preferred；Then, in the presence of chelate titanium complex, addition 60ppm~90ppm (more preferably 70ppm~80ppm) weak acid Magnesium salts, added again after addition 60ppm~80ppm (more preferably 65ppm~75ppm) without aromatic rings as substituent 5 valencys phosphate.

Esterification process can use the multi-stag device for being connected in series at least two reactor, be flowed back in ethylene glycol Under conditions of, it will implement while removing by reaction and the water or alcohol generated to outside system.

Esterification process can be carried out with a stage, can also be divided into multiple stages and be carried out.

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

When being divided into multiple stages and carry out esterification process, the temperature preferably 230 of the esterification of the first reactive tank DEG C~260 DEG C, more preferably 240 DEG C~250 DEG C, the preferred 1.0kg/cm of pressure²~5.0kg/cm², more preferably 2.0kg/cm²~ 3.0kg/cm².Preferably 230 DEG C~260 DEG C of the temperature of the esterification of second reactive tank, more preferably 245 DEG C~255 DEG C, pressure For 0.5kg/cm²~5.0kg/cm², more preferably 1.0kg/cm²~3.0kg/cm².In addition, more than the stage implement when being divided into 3 When, the condition of the esterification in interstage is preferably set to the condition between the first reactive tank and end reaction groove.

On the other hand, the esterification reaction product for making to generate in esterification carries out polycondensation reaction and generates condensation polymer.Polycondensation Reaction can be carried out with 1 stage, can also be divided into multiple stages and be carried out.

Next, by esterification reaction products such as the oligomer generated in esterification for polycondensation reaction.The polycondensation reaction Esterification reaction product can be supplied by the polycondensation reaction groove to multiple stages preferably to carry out.

For example, polycondensation reaction condition when being carried out in the reactive tank in 3 stages is preferably as follows mode：First reactive tank Reaction temperature is 255 DEG C~280 DEG C, and more preferably 265 DEG C~275 DEG C, pressure is 100torr~10torr (13.3 × 10^- ³MPa~1.3 × 10^-3MPa), more preferably 50torr~20torr (6.67 × 10^-3MPa~2.67 × 10^-3MPa), second is anti- Answer groove reaction temperature be 265 DEG C~285 DEG C, more preferably 270 DEG C~280 DEG C, pressure be 20torr~1torr (2.67 × 10^-3MPa~1.33 × 10^-4MPa), more preferably 10torr~3torr (1.33 × 10^-3MPa~4.0 × 10^-4MPa), finally The reaction temperature of the 3rd reactive tank in reactive tank is 270 DEG C~290 DEG C, and more preferably 275 DEG C~285 DEG C, pressure is 10torr~0.1torr (1.33 × 10^-3MPa~1.33 × 10^-5MPa), more preferably 5torr~0.5torr (6.67 × 10^- ⁴MPa~6.67 × 10^-5MPa)。

Can also contain in the polyester synthesized as described above Photostabilised dose, it is antioxidant, ultra-violet absorber, fire-retardant The additives such as agent, easy lubrication prescription (particulate), nucleator (crystallizing agent), crystallization Inhibitorses.

In the synthesis of polyester, solid phase is carried out after preferably being polymerize by esterification.By carrying out solid phase Polymerization, can control the moisture content of polyester, crystallinity, polyester the acid number i.e. terminal carboxyl group of polyester concentration and intrinsic viscosity.

Especially, preferably will be solid in 200ppm~1000ppm scope compared with the EG gas concentrations at the end of solid phase Ethylene glycol (EG) gas concentration when phase-polymerization starts is set to higher, more preferably exists in 250ppm~800ppm, further preferably 300ppm~700ppm scope is set to higher and carries out solid phase.Now, by adjusting average EG gas concentration (solid polycondensations Gas concentration when running the beginning jointly with the end of is averaged) control end COOH concentration.That is, by adding EG, itself and end are made COOH is reacted, so as to reduce end COOH concentration.EG preferred 100ppm~500ppm, more preferably 150ppm~ 450ppm, further preferred 200ppm~400ppm.

Also, preferably 180 DEG C~230 DEG C of the temperature of solid phase, more preferably 190 DEG C~215 DEG C, further preferred 195 DEG C~209 DEG C.

Also, solid state polymerization time preferably 10 hours~40 hours, more preferably 14 hours~35 hours, further preferred 18 Hour~30 hours.

Here, polyester preferably has higher hydrolytic resistance.Therefore, the carboxyl-content in polyester is preferably 50 equivalents/t (here, t represents ton, ton represents 1000kg.) below, more preferably 35 equivalents/below t, more preferably 20 equivalents/t with Under.If carboxyl-content is 50 equivalents/below t, keep hydrolytic resistance, the damp and hot intensity through constantly can be declined be suppressed to compared with It is small.From the viewpoint of the cementability for keeping and being formed between the layer (such as resin bed) of polyester, the lower limit of carboxyl-content is excellent Select 2 equivalents/t, more preferably 3 equivalents/t.

Carboxyl-content in polyester can pass through polymerization catalyst species, film forming condition (film temperature and time), solid phase Polymerization, additive (end-capping reagent etc.) etc. are adjusted.

(end-capping reagent)

The white polyester film of the disclosure can further improve hydrolytic resistance (weatherability) by adding end-capping reagent.

The end-blocking that it is 0.1~10 mass % relative to the gross mass of polyester that the white polyester film of the disclosure, which can contain, Agent.End-capping reagent enters relative to above-mentioned addition more preferably 0.2~5 mass % of the gross mass of polyester contained in polyester film One step preferably 0.3~2 mass %.

Poly- ester hydrolysis passes through H caused by carboxyl as molecular end etc.⁺Catalytic effect and be accelerated, therefore in order to carry High hydrolytic resistance (weatherability), addition are effective with the end-capping reagent that terminal carboxyl group is reacted.

If the addition of end-capping reagent is more than 0.1 mass % relative to the gross mass of polyester, it is weather-proof easily to show raising Property effect, if below 10 mass %, then can suppress to play polyester the effect as plasticizer, it is strong so as to suppress mechanics Degree, heat resistance decline.

As end-capping reagent, epoxide, carbodiimide compound, oxazoline compounds, carbonate compound can be enumerated Thing etc., preferably higher with the compatibility of PET (PET) and the high carbodiimide of end-blocking ability.

End-capping reagent (especially carbodiimide end-capping reagent) is preferably HMW.By using the end-capping reagent energy of HMW Enough reduce the volatilization in melted masking.The molecular weight of end-capping reagent preferably 200~100,000, more preferably 2000~80,000, further preferably 10000~50,000.If the molecular weight of end-capping reagent (especially carbodiimide end-capping reagent) is in the range of 200~100,000, easily uniformly Ground is scattered in polyester, easily shows the effect for improving weatherability.Also, end-capping reagent is difficult to volatilize in extrusion, film, easily Show the effect for improving weatherability.

In addition, the molecular weight of end-capping reagent refers to weight average molecular weight.

Carbodiimide class end-capping reagent：

Carbodiimide compound with carbodiimide has a functionality carbodiimide and multi-functional carbodiimide, makees For a functionality carbodiimide, can enumerate dicyclohexylcarbodiimide, DIC, dimethyl carbodiimide, Diisobutyl carbodiimide, dioctyl carbodiimide, ter /-butylisopropyl carbodiimide, diphenyl carbodiimide, di-t-butyl Carbodiimide, two-betanaphthyl carbodiimide etc..Especially preferably dicyclohexylcarbodiimide and DIC.

As multi-functional carbodiimide, it is preferable to use the carbodiimide of the degree of polymerization 3~15.Specifically, can 1,5- naphthalenes carbodiimide, 4,4 '-diphenyl methane carbodiimide, 4,4 '-diphenyldimethyhnethane carbodiimide, 1 are exemplified, 3- phenylenes carbodiimide, 1,4- phenylene vulcabonds, 2,4- toluene carbodiimide, 2,6- toluene carbodiimide, 2,4- The mixture of toluene carbodiimide and 2,6- toluene carbodiimides, hexa-methylene carbodiimide, hexamethylene -1,4- carbodiimides, Xylylene carbodiimide, isophorone carbodiimide, dicyclohexyl methyl hydride -4,4 '-carbodiimide, hexahydrotoluene carbon two Imines, tetramethyl xylylen carbodiimide, 2,6- diisopropyl phenyls carbodiimide and 1,3,5- triisopropylbenzenes -2,4- Carbodiimide etc..

Carbodiimide compound produces isocyanates gas by thermal decomposition, therefore the preferably high carbon two of heat resistance is sub- Amines.In order to improve heat resistance, molecular weight (degree of polymerization) is more high more preferred, more preferably by the end of carbodiimide compound It is set to the high structure of heat resistance.Also, once cause thermal decomposition, then easily cause further thermal decomposition, it is therefore desirable to as far as possible The extrusion temperature of polyester is set to low temperature etc..

The carbodiimide of end-capping reagent is also preferably the carbodiimide with cyclic structure (for example, Japanese Unexamined Patent Publication 2011- The described carbodiimide with cyclic structure in No. 153209 publications).Even the carbodiimide with cyclic structure is low Molecular weight, also show the carbodiimide identical effect with above-mentioned HMW.Because the terminal carboxyl group and ring-type of polyester Carbodiimide carry out ring-opening reaction, wherein a side is reacted with the polyester, the opposing party of open loop is carried out instead with other polyester Answer and turn into molecular weight, therefore can suppress to produce isocyanates gas.

In the carbodiimide with cyclic structure, in the disclosure preferred end-capping reagent be comprising with carbodiimide and its First nitrogen and the second nitrogen are by binding groups and the carbodiimide compound of cyclic structure that is bonded.In addition, end-capping reagent is more preferably For comprising the first nitrogen with least one carbodiimide adjacent with aromatic rings and the carbodiimide adjacent with aromatic rings and Second nitrogen is by binding groups and the carbodiimide (also referred to as aromatic cyclic carbodiimide) of the cyclic structure that is bonded.

Aromatic cyclic carbodiimide can have multiple cyclic structures.

Aromatic cyclic carbodiimide can also be preferably using first of intramolecular without the carbodiimide of more than 2 Nitrogen and the second nitrogen are by linking group and the aromatic series carbon diimine of ring structure being bonded, i.e., monocyclic aromatic series carbon diimine.

Cyclic structure have 1 carbodiimide (- N=C=N-) and its first nitrogen and the second nitrogen by binding groups and Bonding.Only there is 1 carbodiimide in one cyclic structure, when having multiple cyclic structures such as loop coil in molecule, If having 1 carbodiimide in each cyclic structure for be bonded to spiro-atom, there can be multiple carbon as compound Di-imidogen.Atomicity preferably 8~50, more preferably 10~30, further preferred 10~20, particularly preferred 10 in cyclic structure ~15.

Here, the atomicity in cyclic structure refers to the quantity for the atom for directly constituting cyclic structure, such as if 8 yuan of rings It is then 8, is then 50 if 50 yuan of rings.If the atomicity in cyclic structure is more than 8, the stabilization of Cyclic carbodiimide compound Property increase, easily keeping and use.Also, from the viewpoint of reactivity, the higher limit on ring element number does not limit especially System, but the synthesis difficulty of the Cyclic carbodiimide compound of less than 50 atomicity is smaller, can be suppressed to cost relatively low.From The viewpoint considers that the atomicity in cyclic structure preferably selects 10~30 scope, more preferably selects 10~20 scope, especially Preferably select 10~15 scope.

As the concrete example of the carbodiimide class end-capping reagent with cyclic structure, following compound can be enumerated.But this Invention is not limited by example in detail below.

[chemical formula 1]

Epoxies end-capping reagent：

As the preference of epoxide, epihydric alcohol ester compound and glycidyl ether compound etc. can be enumerated.

As the concrete example of epihydric alcohol ester compound, glycidyl benzoate, p t butylbenzoic acid contracting can be enumerated Water glyceride, p- toluic acid ethylene oxidic ester, cyclohexane-carboxylic acid ethylene oxidic ester, n-nonanoic acid ethylene oxidic ester, stearic acid shrink Glyceride, bay acid glycidyl ester, palm acid glycidyl ester, behenyl acid glycidyl ester, tertiary carbonic acid glycidyl ester, oil Acid glycidyl ester, linoleic acid ethylene oxidic ester, flax acid glycidyl ester, behenyl acid glycidyl ester, stearic acid shrink sweet Grease, 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, tetrahydrochysene O-phthalic acid diglycidyl ester, cyclohexane dicarboxylic acid 2-glycidyl ester, adipic acid 2-glycidyl ester, butanedioic acid two contract Water glyceride, Diglycidyl Sebacate, dodecanedioic acid 2-glycidyl ester, octadecane dicarboxylic acids 2-glycidyl ester, Trimellitic acid three-glycidyl ester, pyromellitic acid tetra glycidyl ester etc., these can use one kind or two or more.

As the concrete example of glycidyl ether compound, phenyl glycidyl ether, o- phenyl glycidyl can be enumerated Double (β, γ-epoxy radicals propoxyl group) butane of ether, 1,4-, double (β, γ-epoxy radicals propoxyl group) hexanes of 1,6-, 1,4- double (β, γ-ring Epoxide propoxyl group) benzene, 1- (β, γ-epoxy radicals propoxyl group) -2- Ethoxyethanes, 1- (β, γ-epoxy radicals propoxyl group) -2- benzene first Acyloxy ethane and by 2,2- it is double-[p- (β, γ-epoxy radicals propoxyl group) phenyl] propane, 2,2- be double-(4- hydroxy benzenes Base) propane, 2,2- be double-bisglycidyl base polyethers obtained from the reaction of the bis-phenol such as (4- hydroxy phenyls) methane and epichlorohydrin Deng these can use one kind or two or more.

Oxazoline class end-capping reagent：

Zuo Wei oxazoline compounds, You Xuan bisoxazoline compounds, specifically, 2,2 ' can be exemplified-bis- (2- oxazoles Quinoline), 2,2 '-bis- (4- methyl -2- oxazolines), 2,2 '-bis- (4,4- dimethyl -2- oxazolines), 2,2 '-bis- (4- ethyl -2- Evil Oxazoline), 2,2 '-bis- (4,4 '-diethyl -2- oxazolines), 2,2 '-bis- (4- propyl group -2- oxazolines), 2,2 '-it is bis- (4- butyl - 2- oxazolines), 2,2 '-bis- (4- hexyl -2- oxazolines), 2,2 '-bis- (4- phenyl -2- oxazolines), 2,2 '-it is bis- (4- cyclohexyl - 2- oxazolines), 2,2 '-bis- (4- benzyl -2- oxazolines), 2,2 '-p-phenylene double (2- oxazolines), 2,2 '-- phenylenes Double (2- oxazolines), 2,2 '-o- phenylene double (2- oxazolines), 2,2 '-p-phenylene double (4- methyl -2- oxazolines), 2, 2 '-p-phenylene double (4,4- dimethyl -2- oxazolines), 2,2 '-- phenylene double (4- methyl -2- oxazolines), 2,2 ' - Double (the 2- Evil of-phenylene double (4,4- dimethyl -2- oxazolines), 2,2 '-ethylenebis (2- oxazolines), 2,2 '-tetramethylene Oxazoline), 2,2 '-hexamethylene bis (2- oxazolines), 2,2 '-eight di-2-ethylhexylphosphine oxides (2- oxazolines), the double (2- of 2,2 '-decamethylene Oxazoline), 2,2 '-ethylenebis (4- methyl -2- oxazolines), 2,2 '-tetramethylene double (4,4- dimethyl -2- oxazolines), 2,2 ' -9,9 '-biphenoxyl ethane double (2- oxazolines), 2,2 '-cyclohexylidene double (2- oxazolines), 2,2 '-diphenylene are double (2- oxazolines) etc..Among those, from the viewpoint of the reactivity with polyester, can with most preferably with 2,2 '-bis- (2- Evil Oxazoline).In addition, as long as the bisoxazoline compounds enumerated in above-mentioned realize the purpose of the present invention, then can be used alone, Can also be simultaneously using two or more.

This end-capping reagent is for example made an addition in the resin bed on polyester film, and polyester and end-capping reagent will not also react, therefore Need to mix when manufacturing polyester film and make it directly react with polyester molecule.

(white particles)

The white polyester film of the disclosure contains relative to the white particles that total film mass is 2~10 mass %.Pass through The content of contained white particles is more than 2 mass % in the white polyester film of the disclosure, can obtain higher light reflection Property, by the way that for below 10 mass %, higher intensity can be kept.

Consider from the viewpoint, the contents of white particles is relative to white polyester film, preferably 2~10 mass %, more preferably 2.5~8.5 mass %.

The content of contained white particles can be measured by following methods in white polyester film.

3g films are weighed in crucible as measure sample, in electric dry oven, carry out heating for 120 minutes at 900 DEG C.So Afterwards, crucible is taken out after being cooled off in electric dry oven, determines the quality of the ash content remained in crucible.The ash content be white particles into Point, using the quality of ash content divided by determine the quality of sample and be multiplied by the content (quality %) of 100 value as white particles.

If, can be according to the addition of the white particles (Chinese white) as raw material in addition, before film is manufactured Obtain content.

Preferably 0.03~0.25 μm of the average grain diameter of white particles, more preferably 0.07~0.25 μm, further preferred 0.1~ 0.2μm.If the average grain diameter of white particles is 0.03~0.25 μm, not only the whiteness of film is improved, Er Qierong The average area of every 1 that film profile is easily formed from white particles is 0.010~0.050 μm²/ hole.

The average grain diameter of contained white particles is by using electron microscope in white polyester film in the disclosure Method is obtained.Specifically, based on following methods.

Using the white particles in the section of the thickness direction of scanning electron microscope viewing film, according to the big of particle Small and suitably change multiplying power, shooting photo simultaneously amplifies duplicating.For randomly selected at least 200 particles, to the outer of each particle Week is tracked.By image analysis apparatus, from the diameter of equivalent circle of these tracking determining image particles, by their average value As average grain diameter.

If, can be to being selected at random from the white particles (Chinese white) as raw material in addition, before film is manufactured At least 200 particles selected, obtain average grain diameter in the same manner as described above.

As white particles contained in the white polyester film of the disclosure, such as wet type and dry type titanium dioxide can be used Silicon, cataloid, calcium carbonate, alumina silicate, calcium phosphate, aluminum oxide, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide (zinc In vain), antimony oxide, cerium oxide, zirconium oxide, tin oxide, lanthana, magnesia, barium carbonate, zinc carbonate, basic lead carbonate (white lead), Barium sulfate, calcium sulfate, lead sulfate, zinc sulphide, mica, mica titanium, talcum, clay, kaolin, lithium fluoride, calcirm-fluoride etc..From into This, it is acquired from the viewpoint of, preferably titanium oxide and barium sulfate.And it is possible to aluminum oxide, silica are implemented to particle surface Deng inorganic processing, the organic process of siloxanes or alcohol etc. can also be implemented.

Wherein, preferred titanium oxide, by using titanium oxide, light reflective can be played and even if also can under light illumination Play excellent durability.

There is rutile-type and Detitanium-ore-type in titanium oxide, the preferred addition of the white polyester film in the disclosure is with rutile-type Make its whitening as the Titanium particles of main body.The spectral reflectance of the ultraviolet of rutile-type is very big, in contrast, Detitanium-ore-type has the characteristic of the absorptivity of ultraviolet larger (spectral reflectance is smaller).It is conceived in the crystal habit of titanium oxide Dichroism difference, by using the UV absorbing properties of rutile-type, can be improved in backboard used for solar batteries Light resistance (by the durability of UV-induced deterioration).Thus, even if substantially other ultra-violet absorbers are not added, in light Film durability under irradiation is also excellent.Therefore, it is not likely to produce and caused pollution and cementability is oozed out by ultra-violet absorber Decline.

In addition, as described above, the Titanium particles involved by the disclosure preferably using rutile-type as main body, it is described herein " main body " refer to Titanium Dioxide Rutile Top grade amount in total Titanium particles more than 50 mass %.

Also, it is preferred that the anatase-type titanium oxide amount in total Titanium particles is below 10 mass %.More preferably 5 mass % Hereinafter, particularly preferred 0 mass %.Titanium Dioxide Rutile Top grade and anatase-type titanium oxide can according to x-ray structure diffraction or point Optical absorption characteristics are distinguished.

On Titanium Dioxide Rutile Top grade particle, particle surface can be entered using inorganic material such as aluminum oxide, silica Row surface treatment, the organic materials such as siloxanes, alcohol can also be utilized to implement surface treatment.Titanium Dioxide Rutile Top grade can coordinate Before polyester, adjust particle diameter using purifying process or remove oversize grain.As the industrial method of purifying process, crush Aeropulverizer or ball mill can be for example applicable in method, as stage division, such as dry type or Wet-type centrifugal separation can be applicable.

In the disclosure, the white particles of organic material can be also used.As the white particles of organic material, preferably it is resistant to Hot particle in polyester film, such as the particle comprising crosslinked resin can be used, specifically, it can use and utilize two Polystyrene that vinyl benzene is crosslinked etc..

The white polyester film of the disclosure can contain one kind or two or more white particles.When containing of more than two kinds white During colored particle, the total content of white particles is set to 2~10 mass %.

(hole)

The white polyester film of the disclosure is 0.010 with the average area of every 1 on the section in film thickness direction ~0.050 μm²/ hole (cavity).Hole in the white polyester film of the disclosure is drawn to assign weatherability Stretch and peel off and formed on the interface of white particles and polyester, the part for the white particles being present in cavity is also included within The interior area as hole.

Average area by every 1 hole contained in film is 0.010 μm²/ more than, can be stretched sufficiently and Higher weatherability is assigned, by for 0.050 μm²/ below, can reduce it is long-term be externally exposed air when moisture to hole Immersion amount in gap, suppress hydrolysis, so as to suppress to produce the cleavage fracture of film.

Considering from the viewpoint, the average area of every 1 hole in the section in film thickness direction is preferably 0.01~ 0.05μm²/, more preferably 0.02~0.05 μm²/.

On the section of the thickness direction of film, the ratio of the gross area (hole occupied area) preferably shared by hole is 0.5~3%.If the ratio of the hole in film is more than 0.5%, it can be stretched sufficiently and assign higher weatherability, Light reflective also becomes abundant.On the other hand, if the ratio of the hole in film is less than 3%, it is externally exposed for a long time During air, it can suppress to hydrolyze, so as to suppress to produce the cleavage fracture of film.

Consider from the viewpoint, the gross area (occupied area) shared by hole in the section of the thickness direction of film is more preferably For 0.6~3%, more preferably 0.6~2.8%.

Above-mentioned fine cavity (hole) in the presence of the white polyester film of the disclosure can mainly be derived from leucoplastid Son and formed.In addition, the hole from white particles refers to cavity around white particles be present, such as can be poly- in white Ester film cross sectional photograph as obtained from electron microscope is first-class to be confirmed.In addition, there is also the white particles of more than 2 Primary particle cohesion and around aggregated particle formed with cavity hole or in above-mentioned observation operation white particles take off Fall and the hole of white particles is not present in hole.

The measure of the average area of the occupied area of contained hole and every 1 hole in the white polyester film of the disclosure Method uses method described in embodiment.

Also, in order to increase whiteness, the white polyester film of the disclosure is further preferably increased using the fluorescence of thiophene diyl etc. White agent.The preferable addition of fluorescent whitening agent is more than 0.01 mass % and below 1 mass %, more preferably 0.05 mass % with Upper and below 0.5 mass %, further preferred more than 0.1 mass % and below 0.3 mass %.If within the range, easily The effect of light reflectivity being improved, xanthochromia caused by thermal decomposition during as extruding being suppressed, is declined so as to suppress reflectivity. As this fluorescent whitening agent, such as Eastman Kodak Company OB-1 etc. can be used.

(thickness)

The thickness of the white polyester film of the disclosure is preferably 280~500 μm.If the thickness of film is more than 280 μm, There can be higher proof voltage.On the other hand, if the thickness of film is less than 500 μm, film during film can be suppressed Heating cooling capacity decline caused by hydrolytic resistance decline, it is and higher negative without applying to stretching-machine when film stretches Lotus and can be stretched.

Consider from the viewpoint, the thickness of film is more preferably 290~450 μm.

The assay method of the thickness of the white polyester film of the disclosure uses method described in embodiment.

(intrinsic viscosity)

In the white polyester film of the disclosure, the intrinsic viscosity (IV of preferred film：Intrinsic viscosity) be 0.65~0.85dL/g.

If the IV of film is more than 0.65dL/g, sufficient weatherability can obtain.On the other hand, if the IV of film is Below 0.85dL/g, then it can suppress the shearing heating in extrusion operation when manufacturing film, decline so as to suppress anti-hydrolytic performance.

Consider from the viewpoint, the IV of film is more preferably 0.67~0.80dL/g, more preferably 0.68~0.77dL/ g。

The IV of the white polyester film of disclosure assay method uses method described in embodiment.

(tearing strength)

In the white polyester film of the disclosure, when tearing strength to be set to P (mN), the thickness of film be set into t (μm), It is preferred that P/t is 6.5~13.5mN/ μm.

If the tearing strength (P/t) of the per unit thickness of film is more than 6.5mN/ μm, sky is externally exposed for a long time During gas, it can suppress to produce the cleavage fracture of film.On the other hand, if the tearing strength (P/t) of the per unit thickness of film is Less than 13.5mN/ μm, then it can assign sufficient weatherability.

Consider from the viewpoint, the tearing strength (P/t) of the per unit thickness of film is more preferably 7.0~13.5mN/ μm, entered One step is preferably 7.0~13.0mN/ μm.

The assay method of the tearing strength of the white polyester film of the disclosure uses method described in embodiment.

(end carboxy concentration)

In the white polyester film of the disclosure, preferably end carboxy concentration is 5~25 equivalents/ton.End carboxy concentration Referred to as acid number (Acid value), it is designated as sometimes " AV ".In addition, in this specification, " equivalent/ton " refers to every 1 ton of mole Equivalent, it is designated as sometimes " eq/t ".

If the end carboxy concentration in polyester film is more than 5 equivalents/ton, the carboxyl (COOH yls) on surface will not be very few (that is, polarity will not be too low), there can be the higher cementability with the different kinds material such as other resin beds.

On the other hand, the H of the COOH bases of polyester molecule end⁺Promote to hydrolyze as catalyst.If in polyester film End carboxy concentration is below 25 equivalents/ton, then can suppress hydrolytic resistance decline.

End carboxy concentration is the value determined by the following method.That is, resin determination sample 0.1g is dissolved in benzylalcohol 10ml and then add chloroform and obtain mixed solution, and to the mixed solution and dripping phenolic red indicator.Utilize titer (0.01mol/L KOH- benzylalcohols mixed solution) is titrated to the solution, and end carboxy concentration is obtained according to dripping quantity.

＜ stretches the manufacture method ＞ of white polyester film

The method for manufacturing the stretching white polyester film of the disclosure is not particularly limited, such as the stretching white of the disclosure Polyester film can be manufactured preferably by the following method.

That is, the manufacture method of the stretching white polyester film of the disclosure has：Extrusion operation, Starting Material Polyester and white will be contained After the mixture melting extrusion of colored particle, cooled down and be molded non-stretched white polyester film；And stretching process, will not To being stretched, stretching process has in length at least one party of the white polyester film of stretching along its length and in width The 1st~the N stretching process that at least one party in degree direction and width is upwards stretched white polyester film, n-th Stretching process continues the (n-1)th stretching process and carried out, and compared with the (n-1)th stretching process, it is poly- to increase white in the n-th stretching process Draw speed of the ester film on a direction of length direction or width, in N stretching process, draft temperature is set to 140~180 DEG C, and be set to a direction of the white polyester film before starting relative to the 1st stretching process length increase by 8~ 25%/second one direction length draw speed.Here, N is more than 2 integer, n is 2~N integer.

The manufacture method of the stretching white polyester film of the disclosure carries out heat-setting process, heat preferably after stretching process Relaxation process.

And it is possible to after non-stretched white polyester film is formed and before stretching process, or carrying out along one After the stretching in direction and before carrying out stretching in another direction, carry out for form priming coat production line in apply (inline coat)。

Hereinafter, each operation is specifically described, but the manufacture method of the white polyester film of the disclosure does not limit In following methods.

(extrusion operation)

In extrusion operation, after the mixture melting extrusion containing Starting Material Polyester and white particles, cooled down and Form non-stretched white polyester film and (below, be designated as non-stretched film sometimes.).

For example, using white particles such as foregoing polyester, titanium oxide as raw material, after being dried, melted, make gained Then the molten mass (melt) arrived, is extruded, and make it by gear pump and filter via mould to chill roll (casting drum) Cooling and solidifying, thus obtains non-stretched white polyester film.Melting is carried out using extruder, can also be squeezed using single screw rod Go out machine, multi-screw extruder more than twin-screw can also be used.

Known various methods can be used by coordinating into polyester film during white particles., can as its exemplary process To enumerate following methods.

(A) white particles are added before the ester exchange reaction or esterification when terminating synthesizing polyester, or started The method that white particles are added before polycondensation reaction.

(B) white particles and the method for carrying out melting mixing are added into polyester.

(C) manufacture with the addition of the masterbatch (also referred to as " master batch ") of a large amount of white particles by above-mentioned (A) or (B) method, Masterbatch and the polyester without white particles or containing a small amount of Chinese white are kneaded and white particles containing ormal weight Method.

(D) master batch of above-mentioned (C) and the method for carrying out melting mixing are directly used.

Wherein, the method for preferably above-mentioned (C), i.e. the masterbatch that manufacture with the addition of a large amount of white particles (below, is designated as sometimes “MB”.), masterbatch and the polyester without white particles or containing a small amount of Chinese white are kneaded and the white containing ormal weight The method of particle is (below, sometimes referred to as " mother material ".).Also, can also use will the polyester that not be dried in advance and white Colored particle is put into extruder, while being de-gassed to moisture and air etc. while making the method for masterbatch.Additionally, it is preferred that make Masterbatch is made with the polyester slightly dried in advance, the acid number that can now suppress polyester rises.In this case, may be used With enumerate deaerate while extrude method, utilize method for through fully dry polyester, being not added with deaerating and extruding etc..

For example, make the polyester resin put into during masterbatch (MB) preferably reduces moisture rate beforehand through dry.As drying Condition, it is dry more than 1 hour, more preferably more than 3 hours at preferably 100~200 DEG C, more preferably 120~180 DEG C, further It is preferred that more than 6 hours.Thus, fully dry to making the amount of moisture of polyester resin turn into preferred below 50ppm, more preferably 30ppm Below.

The method being pre-mixed is not particularly limited, and can is the method that batch is carried out, can also be passed through single screw rod Or mixing extruder more than twin-screw is pre-mixed.When deaerating while when making masterbatch, it is preferred to use such as inferior side Method：Polyester resin is melted at a temperature of 250 DEG C~300 DEG C, preferably 270 DEG C~280 DEG C, in pre- kneading machine set 1, It is preferred that the degassing mouth of more than 2, carries out more than 0.05MPa, more preferably more than 0.1MPa continuous sucking degassing, maintains mixer Interior decompression.

The extrusion of molten resin (melt) is preferably carried out under vacuum exhaust or inert gas atmosphere.

Melting temperature in extruder is preferably carried out below the fusing point of used polyester to+80 DEG C of fusing point, more preferably Below+70 DEG C of more than+10 DEG C of fusing point and fusing point, more preferably below+60 DEG C of more than+20 DEG C of fusing point and fusing point.If squeeze The melting temperature gone out in machine is more than+10 DEG C of fusing point, then resin fully melts, on the other hand, below+70 DEG C of fusing point, then The decomposition of polyester etc. can be suppressed, therefore preferably.Additionally, it is preferred that before raw material is put into extruder, in advance to Starting Material Polyester It is dried, preferable moisture content is 10ppm~300ppm, more preferably 20ppm~150ppm.

For the purpose of further improving hydrolytic resistance end-capping reagent can be added when material resin is melted.

End-capping reagent can be together directly appended in extruder with polyester etc., but from the viewpoint of extrusion stability, it is excellent Choosing is put into extruder after being pre-formed polyester and masterbatch.

The molten mass (melt) being extruded is cast on casting drum (chill roll) by gear pump, filter, mould. The shape of mould can be any one in T-shaped mould tool, coat hanger die, fish tail.On casting drum, electrostatic can be used Application method makes molten resin (melt) be adhered on chill roll.The surface temperature of casting drum can be set to substantially 10 DEG C~40 ℃.Preferred more than the 0.5m of diameter and below 5m, more preferably more than 1m and below 4m of casting drum.The actuating speed of casting drum (linear velocity of most peripheral) preferably 1m/ more than minute and below 50m/ minutes, more preferably 3m/ it is more than minute and 30m/ minutes with Under.

(stretching process)

In stretching process, by the non-stretched white polyester film formed in extrusion operation (below, otherwise referred to as not Oriented polyester film.) (MD along its length：Machine Direction (operating direction) and width (TD： Transverse Direction (transverse direction)) at least one party to being stretched.

Also, stretching process has at least one party of the white polyester film along its length and in width to progress 1st~the N stretching process of stretching, the n-th stretching process continues the (n-1)th stretching process and carried out, with the (n-1)th stretching process phase Than, increase draw speed of the white polyester film on a direction of length direction or width in the n-th stretching process, In N stretching process, draft temperature is set to 140~180 DEG C, and is set to the white before starting relative to the 1st stretching process and gathers The draw speed of the length in the length increase direction of 8~25%/second one in one direction of ester film.

By non-stretched polyester film along its length or when width is stretched, at stretching initial stage, by compared with Stretching to suppress the crystallization of polyester, in the final stage of stretching, the shape being sufficiently heated with polyester under slow draw speed State increases draw speed and is set to desired stretching ratio, and the stripping of white particles and polyester is maintained thus, it is possible to minimally From forming small space on white particles periphery, easily form small hole.

In stretching process, can be by film only along its length or width the single shaft that is stretched of a direction Stretching, stretched along its length with the both direction of width it is biaxial stretch-formed in any one, but from improve it is resistance to From the viewpoint of time property, preferably carry out biaxial stretch-formed, from the viewpoint of stretching is easier to make for, more preferably enter along its length Row stretching is (sometimes referred to as " longitudinal stretching ".) after, stretched in the width direction (sometimes referred to as " cross directional stretch ".).Double In the case that axle stretches, after non-stretched white polyester film is carried out into longitudinal stretching along its length, as along width side To carry out cross directional stretch stretching process (cross directional stretch process), carry out the 1st~the N cross directional stretch process (N be more than 2 it is whole Number).N-th cross directional stretch process (n for 2~N integer) the (n-1)th cross directional stretch process that continues is carried out, with the (n-1)th cross directional stretch Process is compared, and increases the draw speed of white polyester film in the direction of the width in the n-th cross directional stretch process.Also, in N In cross directional stretch process, draft temperature is preferably set to 140~180 DEG C, and is set to before starting relative to the 1st cross directional stretch process White polyester film width length increase by 8~25%/second width length draw speed.

Hereinafter, situation about being stretched in the width direction after being stretched along its length is illustrated.

Fig. 1 roughly represents one of the biaxial stretcher used in the manufacture of the stretching white polyester film of the disclosure Example.Biaxial stretcher 100 is shown with Fig. 1 and is installed on the polyester film 200 of biaxial stretcher 100.Biaxial stretcher 100 possesses 1 couple of ring-shaped guide rail 60a and 60b, it is symmetrically arranged across polyester film 200.

Biaxial stretcher 100 is divided into：The preheating part 10 preheated to polyester film 200；By polyester film 200 along with Direction orthogonal arrow MD is that arrow TD is stretched and the extension section 20 of tensile force is assigned to polyester film；To draw imparting The polyester film of stretch assigns the thermal finalization portion 30 that the state of tensile force is heated；Polyester film through thermal finalization is added Heat and slow down the hot wire-CVD portion 40 of the tensile force of the polyester film through thermal finalization；And the polyester film to have passed through hot wire-CVD portion enters The cooling end 50 of row cooling.

Ring-shaped guide rail 60a at least possess can ring-shaped guide rail 60a edge move gripper 2a, 2b, 2e, 2f, 2i and 2j, ring-shaped guide rail 60b at least possess gripper 2c, 2d, 2g, 2h, the 2k that can be moved at ring-shaped guide rail 60b edge And 2l.Gripper 2a, 2b, 2e, 2f, 2i and 2j grasp polyester film 200 TD one end, gripper 2c, 2d, 2g, 2h, 2k and 2l grasp the TD of polyester film 200 the other end.Gripper 2a~2l is generally known as chuck, fixture etc..

In Fig. 1, gripper 2a, 2b, 2e, 2f, 2i and 2j are moved at the edge along ring-shaped guide rail 60a counterclockwise, are grasped Part 2c, 2d, 2g, 2h, 2k and 2l are moved at the edge along ring-shaped guide rail 60b clockwise.

Gripper 2a~2d grasps the end of polyester film 200 in preheating part 10, with the state in ring-shaped guide rail 60a or 60b edge movement, drawn portion 20, show gripper 2e~2h hot wire-CVD portion 40 advance to show gripper 2i~ 2l cooling end 50.Then, gripper 2a, 2b and gripper 2c, 2d press conveying direction order under the MD of cooling end 50 The end of the end release polyester film 200 of side is swum, is advanced with edge of the state along ring-shaped guide rail 60a or 60b, returned to Preheating part 10.

As a result, polyester film 200 moves along the arrow MD in Fig. 1, preheating part 10, extension section 20, heat are delivered to successively Setting section 30, hot wire-CVD portion 40 and cooling end 50.

Gripper 2a~2l translational speed turns into transporting velocity of the polyester film 200 in grip.

Gripper 2a~2l can change translational speed independently of one another.

Therefore, biaxial stretcher 100 can enter to be about to polyester film 200 in extension section 20 and horizontal be drawn along what TD was stretched Stretch, by changing gripper 2a~2l translational speed, polyester film 200 can also be stretched along MD.

That is, simultaneously biaxial drawing can also be carried out using biaxial stretcher 100.

In Fig. 1, gripper 2a~2l this 12 of the end for the TD for grasping polyester film 200 is illustrate only, but is Support polyester film 200, biaxial stretcher 100 also have gripper (not shown) in addition to 2a~2l.

In addition, it is following, gripper 2a~2l is referred to as " gripper 2 " sometimes.

(preheating part)

Polyester film 200 is preheated in preheating part 10.Before polyester film 200 is stretched in advance heating and So that the cross directional stretch of polyester film 200 is easily carried out.

When the glass transition temperature of polyester film 200 is set into Tg, the film surface temperature of preheating part end point is (below, Also referred to as " preheating temperature ") it is preferably Tg-10 DEG C~Tg+60 DEG C, more preferably Tg DEG C~Tg+50 DEG C.

In addition, preheating part end point refers to the time point for terminating the preheating of polyester film 200, i.e., polyester film 200 is away from pre- The position in the hot region of portion 10.

(extension section)

In extension section 20 by preheated polyester film 200 at least along length direction (the conveying side with polyester film 200 To, MD) orthogonal direction (TD) carries out cross directional stretch and assigns tensile force to polyester film 200.

Along the stretching (cross directional stretch) in the direction (TD) orthogonal with the length direction (conveying direction, MD) of polyester film 200 Refer to that edge is stretched with the direction of the angle of the length direction (conveying direction, MD) vertical (90 °) of polyester film 200.

- longitudinal stretching-

In biaxial stretch-formed, to the length side of the non-stretched white polyester film that is formed in extrusion operation along polyester film To such as progress tensile stress be more than 5MPa and below 15MPa and stretching ratio is the longitudinal direction of more than 2.5 times and less than 4.5 times Stretching.

More specifically, polyester film is guided to the roller group for being heated to more than 70 DEG C and 120 DEG C temperature below, along length Direction (longitudinal direction, the i.e. direction of advance of film) progress tensile stress is more than 5MPa and below 15MPa and stretching ratio is 2.5 times Above and less than 4.5 times, more preferably tensile stress is more than 8MPa and below 14MPa and stretching ratio is more than 3.0 times and 4.0 Longitudinal stretching below times.After longitudinal stretching, carried out preferably by the roller group of more than 20 DEG C and less than 50 DEG C of temperature cold But.

- cross directional stretch-

Cross directional stretch is carried out after longitudinal stretching.Cross directional stretch is preferably carried out using stenter.Will be through longitudinal stretching White polyester film guide to stenter, such as be heated to more than 80 DEG C and less than 180 DEG C of temperature (draft temperature) Stretched in the width direction in atmosphere (cross directional stretch).In stenter, the both ends of polyester film are grasped using fixture, while Heat-treatment zone is conveyed, and an edge and length direction direction at a right angle are that width expands fixture, thus, it is possible to carry out Cross directional stretch.

Stretching in the width direction is set to the 1st~the N cross directional stretch process (N is more than 2 integer), the n-th cross directional stretch Process (n for 2~N integer) the (n-1)th cross directional stretch process that continues is carried out, compared with the (n-1)th cross directional stretch process, n-th Increase the draw speed of white polyester film in the direction of the width in cross directional stretch process.Also, in N cross directional stretch processes In, draft temperature is set to 140~180 DEG C, and be set to the white polyester film before starting relative to the 1st cross directional stretch process The draw speed of the length of length increase by 8~25%/second width of width.

Fig. 2 shows diagrammatically in mode that cross directional stretch is carried out to the stage in the manufacture of the white polyester film of the disclosure One.

In fig. 2, position A be polyester film be located at preheating part and cross directional stretch start before in the state of polyester film Width (TD) one end position.Position B is the state that polyester film is located at thermal finalization portion and cross directional stretch terminates Under polyester film width (TD) one end position.

T1, T2 and T3 are that polyester film is located at extension section and started respectively with the 1st grade, the 2nd grade, the draw speed of 3rd level The position of the one end of the width (TD) of the polyester film of cross directional stretch.The end of the width (TD) of polyester film from Position A in-position B by T1, T2, T3.

In addition, when carrying out cross directional stretch in the disclosure, the change of draw speed is not limited to 3 stages, as long as 2 More than the individual stage, but from the viewpoint of produceability, preferably with 3~8 phasic changes.

In cross directional stretch, it is stretched in T1, T2, T3 each position along TD and the width of film gradually includes greatly.Film edge MD is fed continuously, and the stretching along TD is proceeded by T1, during untill reaching T2, relative to TD with draw angle θ₁ Stretched along TD.Can be according to the transporting velocity along MD and draw angle θ along TD draw speed₁It is adjusted.That is, if edge MD transporting velocity is constant, then more increases draw angle θ₁, more increase along TD draw speed.Draw speed can by relative to Cross directional stretch start before film TD length (width W₀) the incrementss of the width of every 1 second represent.For example, ought be such as When shown in Fig. 2 with draw speed of 3 phasic changes along TD, the width W of film before cross directional stretch will be started₀It is set to 100, If thin-film width is stretched in a manner of the ratio of every 1 second 5 is increased along TD untill reaching T2 from T1, the drawing on TD It is 5%/second to stretch speed.

In present embodiment, during since the stretching along TD untill stretching terminates, what film was conveyed along MD Stage period or continuously increase draw angle and increase draw speed, in N cross directional stretch processes, at 140~180 DEG C Draft temperature and draw speed is increased to relative to the length W for starting the width before stretching in the width direction₀ The draw speed for increasing the length of 8~25%/second width carries out N cross directional stretch.

Here, draft temperature during 200 cross directional stretch of white polyester film represents film surface temperature, can be drawn by being arranged at The temperature control device of width machine is controlled.Draft temperature in cross directional stretch together increases with draw speed, from suppression laterally From the viewpoint of the crystallization of the polyester of the initial stage of stretching, draft temperature when cross directional stretch starts is preferably 80~120 DEG C, more preferably 85~115 DEG C.

On the other hand, from be peeling at the interface of white particles and polyester and from the viewpoint of generating small hole, The draft temperature of N cross directional stretch processes is preferably 140~180 DEG C, more preferably 145~175 DEG C.

In addition, draft temperature is the value for the temperature that the film film surface in stretching process is determined by thermocouple.

In this way, by the stage increasing draw speed in the width direction to carry out cross directional stretch, can control in film Using the size of white particles caused hole as starting point, the last draw speed device to hole of the extension section of progress cross directional stretch process The influence of the control of gap size is maximum.

Extension section first half film temperature than relatively low region slow stretching so that the boundary of white particles and polyester Face, which is peeled off, to be difficult to produce.

On the other hand, in the higher latter half of film temperature, it is stretched to desired multiplying power and assigns weatherability.But It is that, if too fast in latter half draw speed, the stress of stretched polyester exceedes the interfacial adhesion of white particles and polyester, It is peeling between white particles and polyester.On the contrary, if draw speed is excessively slow, the orientation of polyester molecule is insufficient, so as to resistance to Time property deficiency.

If also, it is too fast in first half draw speed, drawn polyester stress exceedes the interface of white particles and polyester Adhesive force, it is peeling between white particles and polyester.On the contrary, if draw speed is excessively slow, the crystallization of polyester is carried out, is gathered Ester is hardened, and the increase of drawn polyester stress, is peeling first between polyester and white particles.

Consider from the viewpoint, the draw speed in the direction of the width of the 1st cross directional stretch process is preferably horizontal relative to the 1st The length of length increase by 4~10%/second width of the width of white polyester film before starting to stretching process Draw speed.For example, when changing horizontal draw speed as shown in Figure 2 with three phases, T2 stretching speed is stretched to from T1 Spend for the draw speed of the 1st cross directional stretch process.

Also, due to foregoing, the draw speed just started after stretching is slower, and polyester is harder, therefore will tie Drawn polyester stress before bundle drawing easily uprises, and easily produces the stripping with white particles.Basis is needed just to start to stretch Afterwards draw speed adjustment close to an end stretching before draw speed, when by the 1st cross directional stretch process in width On draw speed when being set to Sa, the draw speed in the direction of the width of N cross directional stretch processes being set into Sb, preferably stretch Value of the speed than Sb/Sa is 1.5~6.

In cross directional stretch process, preferably progress tensile stress is more than 8MPa and below 20MPa and stretching ratio is 3.4 The above and less than 5 times of cross directional stretch again, it is more than 10MPa and below 18MPa and stretching ratio more preferably to carry out tensile stress For more than 3.6 times and less than 4.5 times of cross directional stretch.

Based on above-mentioned biaxial stretch-formed extension area multiplying power (longitudinal stretching multiplying power × cross directional stretch multiplying power) be preferably 9 times with It is upper and less than 20 times.If area multiplying power be more than 9 times and less than 20 times, can obtain for example stretching after thickness be 250 μm with It is upper and less than 500 μm, planar orientation degree is higher, has more than 30% and less than 40% crystallinity, equilibrium moisture content is 0.1 matter Measure more than % and below 0.25 mass the % polyester film through biaxial orientation.

As biaxial stretch-formed method, as described above, except the stretching of the stretching of length direction and width is separated Beyond the gradually biaxial stretching method carried out, while being the stretching for the stretching and width for carrying out length direction simultaneously Any one in biaxial stretching method.

Also, the draw speed of width is set to constant and carries out the 1st~the N longitudinal directions along its length for example, working as During stretching process, the draft temperature for the 1st~the N cross directional stretch processes that can be equally applicable on foregoing width, stretching Speed, draw speed ratio.

(heat-setting process)

Then, to carrying out thermal finalization processing through biaxial stretch-formed white polyester film.

In heat-setting process, for example, more than 160 DEG C and less than 230 DEG C, preferably more than 170 DEG C and less than 220 DEG C (more It is preferred that more than 180 DEG C and less than 210 DEG C) under, to the heat of film implementation 1 second~60 seconds (more preferably 5 seconds~50 seconds) Processing.

If heat setting temperature is more than 160 DEG C, polyester easily crystallizes, and can enter polyester molecule with the state extended Row immobilization, it is possible to increase hydrolytic resistance.It is entangled with one another in polyester molecule also, if heat setting temperature is less than 230 DEG C Part is difficult to produce slip, can suppress polyester molecule contraction, it is possible to increase hydrolytic resistance.

In addition, the surface temperature of film when heat setting temperature said here is thermal finalization processing.

In the heat-setting process set after stretching process, volatile alkalescence that boiling point is less than 200 DEG C can be made The part volatilization of compound.

Heat-setting process preferably continues cross directional stretch to grasp the state progress in chuck in stenter, now, closes In chuck interval, can be carried out with the width at the end of cross directional stretch, can also further expand or reduced width and carry out.It is logical Cross implementation thermal finalization processing and generate crystallite, it is possible to increase mechanical characteristic and durability.

(hot wire-CVD operation)

It is preferred that continue heat-setting process and carry out hot wire-CVD operation.Hot wire-CVD operation refers to for film, for stress pine Relax and apply heat and make the processing of film shrunk.In hot wire-CVD operation, preferably carried out along at least one direction in longitudinally, laterally Relaxation, slack are preferably vertically and horizontally 1%~30% (relative to the ratio of the width after cross directional stretch), more preferably 2%~ 20%, further preferred 3%~15%.When hot wire-CVD temperature to be set to Tr, heat setting temperature be set into Ts, hot wire-CVD temperature Tr is preferably more than 100 DEG C and more than 15 DEG C lower than Ts of temperature province (100 DEG C≤Tr≤Ts-15 DEG C), more preferably at 110 DEG C Above and more than 25 DEG C lower than Ts of temperature province (110 DEG C≤Tr≤Ts-25 DEG C), particularly preferably more than 120 DEG C and Ts is compared Low more than 30 DEG C of temperature province (120 DEG C≤Tr≤Ts-30 DEG C).

In hot wire-CVD operation, within the above range under conditions of to polyester film carry out hot wire-CVD and somewhat release polyester The tensile force of molecule, hydrolytic resistance is thus maintained, while dimensional stability becomes good, in processing of resulting polyester film etc. Failure is not susceptible in lower procedure.

Transverse relaxation can be implemented by the width for the fixture for reducing stenter.Also, longitudinal relaxation can pass through contracting The adjacent grip separation of small stenter is implemented.This can be by will be attached and contracted with pantograph shape between adjacent fixture The small pantograph shape is realized.Also, also can be after film be taken out from stenter while being conveyed with low-tension while entering Row is heat-treated to be relaxed.Tension force preferred 0N/mm in the per unit sectional area of film²~0.8N/mm², more preferably 0N/mm² ~0.6N/mm², further preferred 0N/mm²~0.4N/mm²。0N/mm²More than 2 pairs of niproll is set when can pass through conveying And in-between implement film (with catenary) relaxation.

(coiling process)

The both ends grasped by fixture of the film taken out of from stenter are trimmed, and both ends are carried out annular knurl processing (impression Processing) batched afterwards.

The preferable width for the film being taken up is 0.8m~10m, more preferably 1m~6m, further preferred 1.2m~4m. Preferably 30 μm~500 μm, more preferably 40 μm~480 μm, further preferred 45 μm~450 μm of thickness.The adjustment energy of this thickness Enough (speed of chill roll and linked by the adjustment of the spray volume of extruder, the adjustment of film speed with the speed of chill roll The adjustment of draw speed etc.) realize.

In addition, the edge part of trimmed film grades, regeneration is recovered by the use of film as resin compound, by sharp again With.Regeneration turns into the film raw material of lower batch white polyester film with film, returns to drying process as described above, successively instead Manufacturing process is carried out again.

Through above process, the white polyester film of the disclosure can be manufactured.

＜ backboard ＞ used for solar batteries

The backboard used for solar batteries of the disclosure includes the white polyester film of the disclosure.

The backboard used for solar batteries of the disclosure can as needed the disclosure white polyester film it is at least one Face sets functional layer.The easy-adhesion layer of bonding force, UV-absorbing layer, weather-proof is improved to adherend for example, can enumerate Property layer etc..

The backboard used for solar batteries of the disclosure due to possessing the white polyester film of the disclosure, therefore it is long-term use of when show Show stable weatherability, cementability and light reflective.

The method that at least one face as the white polyester film in the disclosure sets functional layer, can use roller coat Coating technique known to method, blade edge rubbing method, gravure coating process, curtain coating processes etc..And it is possible to pass through foregoing production Applied in line and form functional layer.

Backboard used for solar batteries at least one face of the stretching white polyester film of the disclosure by having coating shape Into functional layer (coating layer), can further improve any one in weatherability, light reflective and cementability, or assign Other functions.

And it is possible to before coating layer is coated with implement surface treatment (flame treatment, sided corona treatment, corona treatment, UV treatment etc.).

Also, other functional films are further preferably fitted in the white polyester film of the disclosure via adhesive linkage.

＜ solar modules ＞

The solar module of the disclosure includes：Solar cell device；Encapsulant, sealing solar cell member Part；Front side substrate, it is configured in the light surface side of solar cell device more more outward than encapsulant；And aforementioned embodiments Backboard used for solar batteries, be configured in the side opposite with light surface side of solar cell device and more leaned on than encapsulant Outside.

That is, the solar module of the disclosure is configured to, on the incident transparent front side substrate (surface of sunshine Guard block) between the backboard used for solar batteries (back-protective part) of the disclosure that has described configuration by the light of sunshine Energy conversion be electric energy solar cell device, and by the solar cell device being configured between front side substrate and backboard by The encapsulants such as ethane-acetic acid ethyenyl ester (EVA) seal.Possesses the white polyester comprising the disclosure by solar module The backboard used for solar batteries of film, it can suppress to produce backboard used for solar batteries and peel off and be cracked as caused by hydrolysis, and Generating efficiency can be improved with higher reflective light to solar cell device.Therefore, the solar-electricity of the disclosure Pond module can be in the higher generating efficiency of outdoor long-term maintenance.

On the part in addition to solar module and backboard, such as at " photovoltaic power generation system constituent material " It is documented in (China fir this Rong Yi chief editors, Kogyo Chosakai Publishing Co., Ltd.s, issue for 2008).

The front side substrate of the transparency, can be light transmissive from making as long as there is that can make the light transmissive translucency of the sun Suitably selected in base material.From the viewpoint of generating efficiency, the substrate that the transmissivity of light is higher is more preferred, as this substrate, Such as can be preferably with transparent resin substrate such as glass substrate, acrylic resin etc..

As solar cell device, can be applicable the silicon such as monocrystalline silicon, polysilicon, non-crystalline silicon class, copper-indium-gallium-selenium, copper- The various known solar cell devices such as the iii-vs such as indium-selenium, cadmium-tellurium, gallium-arsenic or II-VI group compound semiconductor class.

The white polyester film of the disclosure is preferably as the base film of backboard used for solar batteries, but the disclosure is white The purposes of color polyester film is not limited to backboard used for solar batteries, can also act as in outdoor long-term use of film.Make For concrete example, in addition to the protection film of solar cell, can enumerate building materials film, outdoor advertising film, every Hot film etc..

Embodiment

Hereinafter, the present invention is described in further detail by embodiment, but the present invention is without departing from its objective, Then it is not limited to following examples.In addition, as long as no specifying, then " part " is quality criteria.

[embodiment 1]

The synthesis ＞ of ＜ Starting Material Polyesters resin 1

As shown below, make the directly reaction of terephthalic acid (TPA) and ethylene glycol and water is distilled off, after being esterified, use The direct esterification of polycondensation is carried out under reduced pressure, and polyester resin (Ti catalyst class PET) has been obtained by continuous polymerization unit.

(1) esterification

In the first esterification groove through 1.8 tons of 90 minutes 4.7 tons of high purity terephthalic acids of mixing and ethylene glycol shape The first esterification groove is continuously fed into slurry, and with 3800kg/h flow.In addition, continuously supply citric acid is coordinated in Ti The ethylene glycol solution of the citric acid chelate titanium complex (VERTEC AC-420, Johnson Matthey company systems) of metal, Under agitation, reacted within about 4.3 hours with 250 DEG C of temperature in reactive tank, mean residence time.Now, with Ti additions Citric acid chelate titanium complex is continuously with the addition of in a manner of element scaled value is counted as 9ppm.The acid of resulting oligomer It is worth for 600 equivalents/ton.

Resulting reaction product (oligomer) is transferred to the second esterification groove, under agitation, with warm in reactive tank 250 DEG C of degree, mean residence time are reacted and have obtained the oligomer that acid number is 200 equivalents/ton for 1.2 hours.Second esterification The inside of reactive tank is separated into 3 areas, is counted from the 2nd area by Mg additions by element scaled value as continuous in a manner of 75ppm The ethylene glycol solution of magnesium acetate is supplied, is then counted from the 3rd area by P additions by element scaled value as continuous in a manner of 65ppm The ethylene glycol solution of trimethyl phosphate is supplied.

(2) polycondensation reaction

The esterification reaction product obtained in will be above-mentioned is continuously fed into the first polycondensation reaction groove, under agitation, to react temperature Pressure 20torr (2.67 × 10 in 270 DEG C of degree, reactive tank^-3MPa), mean residence time has carried out polycondensation in about 1.8 hours.

The reaction product that have passed through the first polycondensation reaction groove is transferred to the second polycondensation reaction groove again, in the reactive tank, Under agitation, with pressure 5torr (6.67 × 10 in 276 DEG C of temperature in reactive tank, reactive tank^-4MPa) and the holdup time about 1.2 is small When condition reacted (polycondensation).

Then, the reaction product that have passed through the second polycondensation reaction groove is moved to the 3rd polycondensation reaction groove again, in the reaction In groove, with pressure 1.5torr (2.0 × 10 in 278 DEG C of temperature in reactive tank, reactive tank^-4MPa), the bar of 1.5 hours holdup times Part is reacted (polycondensation) and has obtained PET (PET).Coupled using high-resolution type high-frequency inductor etc. Gas ions mass spectral analysis (HR-ICP-MS；SII Nano Technology Inc. AttoM), to resulting PET (reactions Product) it is determined.Its result is Ti=9ppm, Mg=67ppm, P=58ppm.P somewhat subtracts relative to initial addition Few, deduction is volatilized in the course of the polymerization process.

- solid phase-

The PET of above-mentioned middle polymerization is granulated (diameter 3mm, length 7mm), and it is (special to resulting resin particle Property viscosity number IV=0.60dl/g, end carboxy concentration=16 equivalents/ton) solid phase is implemented as follows.

In solid phase, using -30 DEG C of nitrogen of dew-point temperature, will have been described at 140 DEG C by esterification and The polyester of polymerization heats 7 minutes, and has been carried out for the purpose of set during preventing solid phase Pre-crystallizing.

Then, using the heating nitrogen of -30 DEG C of dew-point temperature, dried 7 hours at 180 DEG C and set the moisture rate in resin For below 50ppm.

Then, after dry polyester resin being preheated into 210 DEG C, nitrogen circulation 50 hours, thus enter at 195 DEG C Solid phase is gone.As nitrogen circulation condition, by using gas ratio (the nitrogen scale of construction of circulation relative to discharge resin Amount) it is set to 1.3m³/ kg, superficial velocity 0.08m/ seconds, glycol concentration 240ppm, water concentration 12ppm, ethylene glycol and water rub You have carried out solid phase by the nitrogen of intrinsic standoff ratio (mole partial pressure of mole partial pressure/water of ethylene glycol) 20.It is above-mentioned mixed in order to be made Gas composition is closed, uses water content 100ppm high-purity ethylene glycol in ethylene glycol washer, and the temperature of washer is set For 35 DEG C.Pressure in washer is located at 0.1MPa~0.11MPa scope.

Then, the resin (750kg/h) discharged from reaction process is cooled to 60 DEG C.

Polyester resin after resulting solid phase is intrinsic viscosity (IV)=0.78dL/g, end COOH amounts (AV)= 9 equivalents/ton.

The making ＞ of ＜ master batches

Added into a part of particle before solid phase in a manner of containing ratio turns into 50 overall mass % of particle Titanium oxide is simultaneously kneaded and produces master batch (masterbatch).

Here, as titanium oxide, ISHIHARA SANGYO KAISHA, LTD. system (trade names have been used：PF-739； Average primary particle diameter=0.25 μm).

The formation ＞ of ＜ non-stretched films

By the PET-1 for finishing solid phase as described above and master batch be separately dried to below moisture content 100ppm it Afterwards, mixed, and put into the hopper of mixing extruder in a manner of titanium oxide amount turns into 4 mass %, melted at 290 DEG C Melt and extrude.In addition, extruder has used the bilateral gas port type rotating Vortex intermeshing twin-screw extrusion for possessing blow vent at two Machine (diameter 110mm).After making the fused mass (melt) by gear pump, filter (20 μm of aperture), from mould extrusion to Cool down on casting drum (chill roll).In addition, applying method by electrostatic, the melt of extrusion is adhered on cooling casting drum. Thus, thickness about 3mm non-stretched PET (PET) film is formd.

The stretching ＞ of ＜ non-stretched films

- longitudinal stretching-

Make non-stretched film by between 2 pairs of different niprolls of peripheral speed, under the following conditions along longitudinal direction (conveying side To) stretched.Here, the draw speed in longitudinal stretching process is with relative to the length of the length direction of non-stretched film Degree, the increase ratio of every 1 second represent.

Preheating temperature：80℃

Draft temperature：90℃

Stretching ratio：3.0 again

Draw speed：300%/second

- cross directional stretch-

Cross directional stretch has been carried out after longitudinal stretching.So that 3 stages increase draft temperature and draw speed and have carried out transverse direction Stretching.Actual conditions is as follows.Here, the draw speed in cross directional stretch process is with relative to the 1st of the film after longitudinal stretching Thin-film width before cross directional stretch process, the increase ratio of every 1 second represent.

Preheating temperature：110℃

The draft temperature of (the 1st cross directional stretch process) after firm beginning cross directional stretch：110℃

The draw speed of (the 1st cross directional stretch process) after firm beginning cross directional stretch：8%/second

The draft temperature in the interstage (the 2nd cross directional stretch process) of cross directional stretch：130℃

The draw speed in the interstage (the 2nd cross directional stretch process) of cross directional stretch：11%/second

Close to an end the draft temperature of (the 3rd cross directional stretch process) before cross directional stretch：145℃

Close to an end the draw speed of (the 3rd cross directional stretch process) before cross directional stretch：15%/second

Cross directional stretch multiplying power (total)：4.2 again

- thermal finalization/hot wire-CVD-

At 190 DEG C, having carried out thermal finalization to the biaxially oriented film after end longitudinal stretching and cross directional stretch, (heat is fixed The type time：10 seconds).

After thermal finalization, reduce stenter width and carried out hot wire-CVD (hot wire-CVD temperature：160℃).

- batch-

After thermal finalization and hot wire-CVD, 10cm has respectively been repaired at both ends.Then, impression is carried out with width 10mm to both ends Process after (annular knurl), batched with tension force 25kg/m.Thin-film width is 1.5m, rolls up a length of 2000m.

The biaxial stretch-formed white polyester film of embodiment 1 has been obtained in the above-described manner.

＜ embodiments 2~11, the ＞ of comparative example 1~6

In addition to the condition and film physical property that change cross directional stretch as shown in table 1, with side same as Example 1 Formula produces the stretching white polyester film of embodiment 2~11 and comparative example 1~6.

[evaluation of film]

Following evaluation has been carried out to the white polyester film after the stretching that is obtained in embodiment and comparative example.By respective survey Determine result and evaluation result is shown in table 1 below.

The area ＞ of ＜ holes

The face of the ratio (hole occupation rate) and every 1 hole shared by the hole in film is have rated by following methods Product.

(measure of hole occupation rate)

1. by slicer, TD, the MD of manufactured white polyester film along film are cut off in a thickness direction.

2. scanning electron microscope is utilized, with 3000 times of cutting profiles for observing all directions.It is random in one direction Shoot more than 9 and obtain the profile image of white polyester film.

3. by image analysis software (ImageJ), from Chinese white stripping and in white from resulting image Gap is formed between particle and polyester so as to the position as hole, and is tracked along the profile of hole.Now, it is present in The part of intrapore white particles be also included within it is interior be used as hole, white particles come off from hole in above-mentioned steps 1~2 And the part in only cavity is similarly tracked.Also, when hole overlaps each other, it is considered as one and is tracked.

4. then, the inframe of tracking is smeared.

5. a pair hole is tracked, the image of smearing is subjected to binaryzation, and be divided into aperture sections and polyester portion.

6. under areal calculation pattern, by the way that the overall pixel count of the pixel count of aperture sections divided by image is determined Ratio shared by 1 image mesopore.

7. above-mentioned 3~6 operation is also carried out on other images, by taking it average, as shared by the hole of all directions Ratio.

8. it is last, being averaged for TD/MD is taken, as the ratio (hole occupation rate) shared by hole.

(measure of the average area of every 1 hole)

I. above-mentioned 1~5 is carried out.

Ii. under areal calculation pattern, the pixel count of hole is obtained, and is converted to area.

Iii. on the other hand, the quantity of hole is counted in the image obtained from 2.

Iv. ii~iii is also implemented on other images.

V. by the quantity of hole that will be obtained in the summation of the area obtained in iv divided by iv and as all directions The area of every 1 hole.

Vi. it is last, being averaged for TD and MD is taken, the average area as every 1 hole.

＜ thickness Gs T.GT.GT

The thickness of polyester film is to use contact film thickness measuring meter (Mitutoyo Corporation systems, ID-F125) The average thickness of the film determined.Specifically, by contact film thickness measuring meter, passed through along the length direction of polyester film 0.5m equal intervals sample 50 points, and in the width direction in film beam overall equal intervals (decile 50 in the direction of the width Point) 50 points are sampled, determine the thickness of 100 points.The average value of the thickness of 100 points obtained by obtaining, as The thickness of polyester film.

＜ intrinsic viscosities ＞

The polyester film produced is dissolved in 1,1,2,2- tetrachloroethanes/phenol (=2/3 [mass ratio]) mixed solvent In, inherent viscosity has been obtained according to the solution viscosity at 25 DEG C of in the mixed solvent.

η sp/C=[η]+K [η] 2C

Here, η sp=(solution viscosity/solvent viscosity) -1, C is dissolving polymer quality (this measure of the solvent per 100ml In be set to 1g/100ml), K is Huggins constant (being set to 0.343).Solution viscosity and solvent viscosity use oersted Wa Er respectively Special viscosimeter is determined.

＜ weatherabilities ＞

Weatherability (the hydrolysis of the polyester film obtained in each example is have rated according to elongation at break conservation rate half-life period Property).On the evaluation of elongation at break conservation rate half-life period, to the polyester film obtained in each example, 120 DEG C, it is relatively wet Preservation processing (heating) is carried out under conditions of degree 100%, and determines the extension at break shown by the polyester film after preserving Rate (%) turns into for 50% holding time (h) relative to the elongation at break (%) shown by the polyester film before preservation, thus Evaluated.

Elongation at break conservation rate half-life period is longer, represents that the weatherability (hydrolytic resistance) of polyester film is more excellent.Here, If elongation at break conservation rate half-life period is more than 95 hours, it may be said that being had excellent weather resistance in practicality.

＜ disbonded tests ＞

(the EVA cementabilities before humid heat treatment)

The polyester film obtained in each example is cut to 20mm width × 150mm length and has prepared 2 sample strips.Will It is cut to EVA sheet (Mitsui Chemicals Fabro, the Inc. EVA sheet of 20mm width × 100mm length： SC50B) sandwich between 2 sample strips, use vacuum lamination apparatus (vacuum laminator of Nisshinbo Co., Ltd.s) Hot pressing is carried out, thus makes it Nian Jie with EVA sheet.Sticking condition now is as follows.

Using vacuum lamination apparatus, carry out 3 minutes after vacuumizing, pressurize 2 minutes and temporary bond at 128 DEG C.So Afterwards, 150 DEG C, the formal bonding processing of 30 minutes have been carried out in drying oven.Consequently, it is possible to 2 be mutually bonded certainly are obtained The part that 20mm is played in one end of sample strip is not be bonded with EVA and the bonding of EVA sheet is bonded with remaining 100mm part comments Valency sample.

By Tensilon (ORIENTEC RTC-1210A), resulting bonding evaluation is not bonded with the EVA of sample It is partially sandwiched between lower clamp, tension test (disbonded test) is carried out with 180 ° of peel angle, draw speed 300mm/ minutes, surveyed The mean peel strength of power detected during 100mm is peeled off is determined.In addition, on peel strength herein, with EVA pieces It is strong that the situation that the generation nearby of the bonding interface of the white polyester film of material bonding is rived and separated from EVA sheet also serves as stripping Degree.Also, when film sample there occurs during rupture, does not use the power detected and is used as " rupture " during 100mm is peeled off Result.

(the EVA cementabilities after humid heat treatment)

By EVA sheet be adhered to by by with it is damp and hot through when before evaluation identical in a manner of carry out and obtained in each example Between 2 sample strips obtained from polyester film cut-out.After bonding, implemented in the environment of 120 DEG C, 100%RH 30 hours Heat (humid heat treatment).

After humid heat treatment, by with it is damp and hot through when before evaluation identical in a manner of carry out tension test (disbonded test), and survey Peel strength is determined.

If before and after humid heat treatment being more than 4N/mm, it may be said that excellent with EVA cementability (peel resistance).

＜ tearing strengths ＞

The tearing strength of polyester film obtained by determining as follows in each example.

Sample thin film is cut out with 2cm width (short side) × 10cm length (long side) respectively on MD, TD.

In the center of short side, length 5cm otch is formed parallel to long side direction, using cupping machine, is utilized Following methods determine stress to it.Measure is in 50% time 25 DEG C, relative humidity progress.

(1-1) grasps one end of notch in the chuck of the side of cupping machine, and the other end is grasped in opposite side Chuck.

(1-2) stretches chuck with 30mm/ minutes, and determines stress.As distance expands between chuck, stress increase, occur Flat part.Using the stress of the flat part as tearing strength, so that number of occurrence n=3 is determined and obtains average value.

(1-3) is measured, using average value as tearing strength on the measure on MD, TD.

＜ proof voltages ＞

On proof voltage, short-circuit magnitude of voltage is determined according to JIS T8010.Specifically, the polyester film of the disclosure Proof voltage by using partial discharge exerciser KPd2050 (KIKUSUI ELECTRONICS CORP. systems) obtain part put Piezoelectric voltage is evaluated.

Proof voltage is also required to the polyester film used in solar module.

＜ reflectivity ＞

Method according to [0084] section of No. 4766192 publications of Japan Patent determines each example being film-made as described above Polyester film reflectivity.

Specifically, in spectrophotometer (Shimadzu Corporation uatomatic recording spectrophotometers " UV- 3150 ") integrating sphere is installed, by standard white plate (Spere Optics company systems white standard plates " ZRS-99-010-W ") on Reflectivity is set to 100% and is corrected, and determines the spectral reflectance of the polyester film of each embodiment and comparative example.In wavelength 400~1200nm region, it is measured with 1nm scales, and has obtained average value.In addition, during measure, at the sample film back side Configure unreflected black hardboard and be determined.

Here, if reflectivity is more than 85%, it may be said that being had excellent weather resistance in practicality.

Show the result in table 1 below.

The weatherability of the white polyester film produced in embodiment, light reflective and peel strength are excellent.Especially will The proof voltage that thickness is set to more than 280 μm of embodiment 1-10 is more than 1kV, suitable for backboard used for solar batteries.Especially The thickness of embodiment 1-9 white polyester film be less than 500 μm, also with easy to manufacture the advantages of.

All disclosures of Japanese patent application 2015-074614 filed in 31 days March in 2015 by reference to and It is incorporated herein.

In this specification described all documents, patent, patent application and technical specification with each document, patent, specially Profit application and technical specification by reference to and by specifically and situation about independently recording to same extent, by reference to and be introduced into this In specification.

Claims

1. one kind stretching white polyester film, it contains polyester and white particles,

The white particles are 2~10 mass % relative to the content of total film mass,

The average area on the section in film thickness direction with every 1 is 0.010~0.050 μm²/ hole.

2. stretching white polyester film according to claim 1, wherein,

On the section of the thickness direction of film, the ratio of the gross area shared by the hole is 0.5~3%.

3. stretching white polyester film according to claim 1 or 2, wherein,

When tearing strength to be set to P, the thickness of film is set into t, P/t is 6.5~13.5mN/ μm.

4. stretching white polyester film according to any one of claim 1 to 3, wherein,

The thickness of film is 280~500 μm.

5. stretching white polyester film according to any one of claim 1 to 4, wherein,

The intrinsic viscosity of film is 0.65~0.85dL/g.

6. stretching white polyester film according to any one of claim 1 to 5, wherein,

The white particles are titanium oxide.

7. a kind of backboard used for solar batteries, it includes the stretching white polyester film any one of claim 1 to 6.

8. backboard used for solar batteries according to claim 7, wherein,

There is coating layer at least one face of the stretching white polyester film.

9. a kind of solar module, it is included：

Solar cell device；

Encapsulant, seal the solar cell device；

Front side substrate, it is configured in the light surface side of the solar cell device more more outward than the encapsulant；And

Backboard used for solar batteries described in claim 7 or 8, it is opposite with light surface side in the solar cell device Side is configured at more more outward than the encapsulant.

10. a kind of manufacture method for stretching white polyester film, it is the stretching any one of manufacturing claims 1 to 6 The method of white polyester film, has：

Extrusion operation, after the mixture melting extrusion containing Starting Material Polyester and white particles, cooled down and molded not The white polyester film of stretching；And

Longitudinal stretching process that the non-stretched white polyester film is stretched along its length and enter in the width direction The cross directional stretch process of row stretching,

The cross directional stretch process has the 1st~the N cross directional stretch processes, and the n-th cross directional stretch process continues the (n-1)th cross directional stretch Process and carry out, compared with the (n-1)th cross directional stretch process, it is poly- to increase the white in the n-th cross directional stretch process Draw speed of the ester film on the width, draft temperature is set to 140 in the N cross directional stretch processes~ 180 DEG C, and it is set to following draw speed in the N cross directional stretch processes：Start relative to the 1st cross directional stretch process The length of the width of the preceding white polyester film makes the length of width increase by 8~25%/second,

N is more than 2 integer, and n is 2~N integer.

11. the manufacture method of stretching white polyester film according to claim 10, wherein,

The draw speed on the width of the 1st cross directional stretch process is 4~10%/second.

12. the manufacture method of the stretching white polyester film according to claim 10 or 11, wherein,

When by the draw speed on the width of the 1st cross directional stretch process be set to Sa, by the N laterally draw Stretch process when the draw speed on the width is set to Sb, value of the draw speed than Sb/Sa be 1.5~6.