KR20140007885A - Laminated body for manufacturing flexible electronic device, biaxially-oriented polyester film used for same, flexible electronic device using same, and manufacturing method therefor - Google Patents

Abstract

An object of the present invention is to provide a laminate having a low curvature (curl) caused by heating as a laminate for use in the manufacture of a flexible electronic device including a step of heating a laminate in which a glass plate and a base film are laminated.
This invention bonds a board | substrate film to the single side | surface of the glass plate of thickness 0.3-0.7 mm, forms a laminated body, forms an electronic circuit on the board | substrate film of the laminated body, and manufactures the flexible electronic device manufactured by peeling a glass plate. As a laminated body used in the above, the thickness of the biaxially-oriented polyester film as a substrate film shall be made into the range which satisfy | fills following formula.
FT ≥ 0.025
FT / GT ² ≤ 0.25
(However, in the above formula, FT is the film thickness (unit: mm), GT is the thickness of the glass plate (unit: mm))

Description

A laminate for manufacturing a flexible electronics device, a biaxially oriented polyester film for use therein, and a flexible electronics device using the same and a method of manufacturing the same. SAME, AND MANUFACTURING METHOD THEREFOR}

The present invention relates to a laminate for producing a flexible electronics device. Moreover, this invention relates to the biaxially-oriented polyester film for flexible electronics device substrate films used for it. Moreover, this invention relates to the flexible electronics device which used the said laminated body, and its manufacturing method.

It is common that the image display apparatus represented by a liquid crystal display, an organic electroluminescent (EL) display, etc. is formed on a glass substrate conventionally. A glass substrate is a material which is excellent in transparency and heat resistance, and is very suitable as a substrate for forming a thin film transistor (TFT) for driving a liquid crystal or an organic EL element. On the other hand, glass substrates have a drawback of high specific gravity and heavy weight that are prone to cracking and cannot be curved. For this reason, in particular, display substrates for mobile devices such as mobile phones and the like have been requested for alternative substrates that are light in weight, hard to crack, and have high safety. As one candidate, the research using a plastic substrate is actively performed, and the research of what is called a flexible display is actively performed using the flexible TFT which formed TFT on such a plastic substrate.

In the board | substrate of a flexible TFT, the outstanding heat resistance is calculated | required from the viewpoint of the temperature in the manufacturing process. Ideally, it is desirable to be able to withstand high temperatures to the same extent as glass. However, since materials with high heat resistance generally have coloring or are very expensive and difficult to mass-produce, efforts are made to lower the process temperature in TFT manufacturing so that a resin substrate having a relatively low heat resistance can be applied. In recent years, a large number of TFTs having sufficient performance even at a process temperature of 200 ° C or less have been reported. In particular, the organic TFT using an organic semiconductor has already reached the practical level.

As the substrate material for the flexible TFT, many proposals have been made so far. For example, a flexible TFT in which a TFT made of a semiconductor material capable of low-temperature molding such as an organic semiconductor or an oxide semiconductor is laminated on a film made of heat-resistant resin such as polyethylene naphthalate, polyimide, polyether sulfone, polycarbonate, or the like. Known. The substrate of such a flexible TFT requires high dimensional stability in addition to heat resistance. That is, with the miniaturization of the image display device, it is necessary to arrange the pixels with high integration, and therefore, the dimensional accuracy of the submicron order is required as the shape reproducibility of the element.

In response to these demands, in particular, polyethylene naphthalate film has high heat resistance and excellent thermal dimensional stability at a high temperature of about 200 ° C., and is excellent in chemical resistance, surface smoothness, and optical properties, and thus has high attention as a substrate material of flexible electronic devices. Is getting.

By the way, the flexible electronics device manufactures by the so-called roll-to-roll method which forms an electronic circuit etc. directly in a roll-shaped plastic film, and a plastic film (finally electronics) through an adhesive layer on a glass substrate. It becomes a board | substrate film in a device), forms an electronic circuit on the film in this glass film laminated body, and peels a film from glass after formation of an electronic circuit, and there exists a method of manufacturing. At the present time, since the former roll-to-roll method is very difficult to secure the precision of electronic circuit formation, the latter method of pasting a film on a rigid glass plate is realistic.

However, in the electronic circuit formation process in the latter method, the heat processing exceeding 180 degreeC, the washing process at room temperature, etc. are repeated. And while the thickness of a glass plate becomes thin recently about 0.3-0.7 mm, when repeating such a heat cycle, a deformation | transformation will arise in a glass film laminated body, a curl will arise by this, and the precision of a lithography cannot be ensured, an electronic circuit pattern It has become a problem that a problem such as this disturbance occurs. Moreover, when the curl by a heat cycle is too big | large, formation of TFT itself is impossible and it becomes a big obstacle in realizing a flexible display.

As a similar problem to this, there is a problem of curl in an organic EL device. As a countermeasure, for example, a structure in which a warpage relaxation substrate is laminated on the rear surface of a TFT substrate to maintain a balance of thermal strain (Patent Document 2), or an anti-curl layer made of a resin layer having a large curing shrinkage ( Patent document 3) etc. are proposed.

However, in such a method of forming a warpage-reducing substrate and an anti-cal layer, since the layers which do not participate in the original function as a display substrate are laminated | stacked, it raises a manufacturing cost or leads to the fall of transparency. Moreover, since the thermodynamic characteristics of a layer need to be closely matched, it cannot be called a realistic countermeasure, such that the application material of an anti-cal layer is limited according to a device structure. Therefore, the countermeasure which does not use such a special anti-cal layer is calculated | required.

Japanese Unexamined Patent Publication No. 2010-225434 Japanese Unexamined Patent Publication No. 2009-199979 Japanese Unexamined Patent Publication No. 2009-81123

Therefore, this invention bonds a board | substrate film to the single side | surface of the glass plate of thickness 0.3-0.7mm, and makes it a laminated body, and forms an electronic circuit on the board | substrate film of the laminated body, and then, flexible electronic device which peels a glass plate. It is an object of the present invention to provide a laminate for use in the manufacture of a flexible electronics device in which curl by heat treatment at the time of electronic circuit formation is suppressed.

Moreover, this invention is a biaxially-oriented polyester used as a flexible electronics device substrate film in a laminated body which can suppress the curl of the laminated body by heat processing at the time of electronic circuit formation in the same manufacturing process. It is an object to provide a film.

Moreover, an object of this invention is to provide the flexible electronics device which used the said laminated body, and its manufacturing method.

Conventionally, curling occurs when heating a laminate in which a plastic substrate is bonded to a substrate having high rigidity such as a glass substrate, or the difference in the amount of expansion during heating due to the difference in thermal expansion coefficient between the glass substrate and the plastic substrate, or the difference in thermal shrinkage. It is thought that it originates from the difference of the shrinkage amount at the time of heating by. However, the present inventors noted that in the above laminate, when a biaxially oriented polyester film is applied as the plastic substrate, it is necessarily curved to the film side when the heating (curves so that the film side is concave).

Here, assuming that the cause of curl is the difference in coefficient of thermal expansion, the coefficient of thermal expansion is obviously smaller on the glass side, so that the expansion by heating is larger on the film side, and the direction in which the curvature is reverse to the above is explained. Can't. In addition, since thermal expansion and cooling contraction are reversible, if curled to the original temperature after heating, there will be no curl remaining, but in reality, the film is curved toward the film side even after heating, and thus, such a phenomenon cannot be explained.

In addition, assuming that the cause of curl is a difference in heat shrinkage rate, the phenomenon in which the heat shrinkage rate is curved toward the film side can be explained. However, according to the examination of the present inventors, even if the film which heat-processed the film previously at high temperature and lowered the thermal contraction rate to almost zero was used, the degree of curl could hardly be seen. From this, it is thought that there is little contribution of the thermal contraction rate as a cause of curl.

Next, the present inventors examined in detail the influence of heating conditions and the physical properties of the polyester film on the degree of curling. As a result, it was found for the first time that the laminate in which the polyester film was adhered to the glass was deformed due to the interfacial stress at the glass-film interface, which occurred upon cooling after heating. That is, according to the examination by the present inventors, in a heating up temperature and high temperature holding | maintenance, a glass-polyester film laminated body does not deform | transform but deforms and curls in a cooling process. Since the interfacial stress caused by the difference in thermal expansion coefficient between the polyester film and the glass is stress-relieved due to the relaxation phenomenon of the polyester molecules heated at or above the glass transition temperature, the degree of curvature of the glass is increased. It is considered that the stress is not caused. On the other hand, when cooling this laminated body, since shrinkage | contraction of a film becomes large by the difference of the thermal expansion coefficient of glass and a polyester film, the interfacial stress of reverse direction during temperature rising arises. However, during cooling, the relaxation time of the polymer chain increases exponentially with the decrease in temperature, and substantially below the glass transition temperature, a mechanism for relieving the interfacial stress generated during cooling does not work. As a result, curl occurs to the film side due to such interfacial stress.

However, there is a limit in reducing the thermal expansion rate of the polyester film, and it does not reach until it suppresses curl alone.

Therefore, in view of the above mechanisms, the present inventors use a biaxially oriented polyester film as a substrate film to be bonded to a glass plate in the above-described manufacturing process of the flexible electronics device. By setting the thickness in a specific range with respect to the thickness of the glass plate, it is possible to suppress the curl effectively by making it less likely to generate and / or relieve stress occurring at the interface of the glass-film during cooling of the laminate. It was found out that it was possible to reach the present invention.

That is, this invention adopts the following structures.

1. For the production of a flexible electronics device produced by bonding a substrate film to one side of a glass plate having a thickness of 0.3 to 0.7 mm to form a laminate, and forming an electronic circuit on the substrate film of the laminate, then peeling the glass plate. The laminated body used as a laminated body for flexible electronics device manufacture which has a biaxially-oriented polyester film in which the film thickness satisfy | fills following formula as a board | substrate film on the single side | surface of the glass plate of thickness 0.3-0.7 mm.

FT ≥ 0.025

FT / GT ² ≤ 0.25

(However, in the above formula, FT is the film thickness (unit: mm), GT is the thickness of the glass plate (unit: mm))

2. Laminated body for flexible electronics device manufacture of said 1 whose polyester which comprises biaxially-oriented polyester film is polyethylene naphthalate.

3. Laminated body for flexible electronics device manufacture of said 1 or 2 whose heat shrinkage ratio after heat-processing 10 degreeC of a biaxially-oriented polyester film for 10 minutes is 0.2 to 1.0%.

4. Lamination for flexible electronics device production in any one of said 1-3 which biaxially-oriented polyester film has a binder layer which contains 50-100 mass% of thermoplastic resin whose glass transition temperature is 80 degrees C or less on at least one side. sieve.

5. Laminated body for flexible electronics device manufacture of said 4 whose Young's modulus of a binder layer is 2-10 GPa.

6. Biaxially-oriented polyester film for flexible electronics device substrate films used as board | substrate film in the laminated body for flexible electronics device manufacture in any one of said 1-5.

7. A biaxially oriented polyester film is bonded to one side of a glass plate having a thickness of 0.3 to 0.7 mm as a substrate film to form a laminate for manufacturing the flexible electronics device according to any one of the above 1 to 5, and then on the substrate film The flexible electronics device manufactured by peeling a glass plate after forming an electronic circuit in it.

8. A biaxially oriented polyester film is bonded to one surface of a glass plate having a thickness of 0.3 to 0.7 mm as a substrate film to form a laminate for manufacturing the flexible electronics device according to any one of the above 1 to 5, and then on the substrate film The manufacturing method of a flexible electronics device which peels a glass plate after forming an electronic circuit in it.

First, the use in this invention is demonstrated.

The biaxially-oriented polyester film of this invention is used as a board | substrate film of a flexible electronics device. Such a flexible electronics device is obtained by bonding a board | substrate film to the single side | surface of a glass plate through an adhesion layer, for example, forming an electronic circuit on this board | substrate film, and peeling a glass plate after that. The final configuration is to have an electronic circuit on the substrate film.

The use of the glass plate in such a step is to reinforce it and to provide rigidity because the flatness of the substrate film cannot be maintained when the electronic circuit is to be formed as it is on the flexible substrate film. . Therefore, although such a glass plate refers to the plate which consists of glass, the plate which consists of other materials which can achieve the said objective can also be employ | adopted. Usually, as a glass plate, the thing excellent in such a quality is used so that a board | substrate film may not be scratched and a device and a process may be contaminated. For example, the optical glass substrate which has the quality of the grade used for display apparatuses, such as a liquid crystal display, can be used.

The thickness of a glass plate is 0.3-0.7 mm, Preferably it is 0.4-0.7 mm, More preferably, it is 0.5-0.7 mm. Thereby, sufficient rigidity can be provided and the objective of using a glass plate is achieved. It is also easy to handle.

A glass plate and a board | substrate film are normally fixed enough to be used through an adhesion layer. The pressure-sensitive adhesive layer is not particularly limited as long as the pressure-sensitive adhesive layer has adhesiveness or adhesiveness to the glass plate and the substrate film, can maintain the adhesiveness or adhesiveness in the device manufacturing process, and can be peeled from the substrate film after electronic circuit formation. For example, it may be a layer made of a thermocompression adhesive, a thermosetting adhesive, and a photocuring adhesive. Moreover, it may be a layer which consists of an acrylic adhesive, for example. Moreover, when peeling a glass plate from a board | substrate film, not only the method of peeling as it is but also the method of peeling after performing the process which weakens adhesiveness or adhesiveness can be employ | adopted, and the adhesive which considered it can be selected.

The thickness of an adhesion layer is a range of 3-300 micrometers, for example. In order to form an adhesion layer, you may apply | coat and form the above adhesive on the single side | surface of a glass plate, and can also use an adhesive sheet.

Next, an electronic circuit is formed on the board | substrate film in a glass plate-substrate film laminated body. Here, an electronic circuit is extraction wiring using TFT, silver paste, etc., for example. In forming an electronic circuit, the heat processing of the temperature of 80-200 degreeC, Preferably the temperature of 120-200 degreeC range is normally performed for about 30 minutes and a maximum of 60 minutes, and it cools to room temperature after that , Washing with ultrapure water or the like is performed. Such heat treatment is generally 80-120 degreeC heat processing, if it is a comparatively low temperature process, and it is 130-200 degreeC heat processing, for example, if it is a comparatively high temperature process. This operation is repeated about 3 times or more normally. And when a glass plate-substrate film laminated body is curled by such a heat cycle, a deformation | transformation will arise in lithography and it will become difficult to form an electronic circuit, or an error will arise in an electronic circuit pattern well. Therefore, it is necessary that a laminated body does not curl well.

After forming an electronic circuit, a glass plate is peeled from the glass plate-substrate film laminated body which has an electronic circuit. At this time, when it has an adhesion layer, an adhesion layer is also peeled. The board | substrate film which has the electronic circuit obtained in this way has flexibility, and is used as a flexible electronics device.

The laminated body of this invention is used as a glass plate-substrate film laminated body in the said process.

The biaxially-oriented polyester film of this invention is used as a board | substrate film in the above.

Hereinafter, the present invention will be described in detail. In addition, in this invention, the film production direction of a film, ie, a machine axis direction, may be called a longitudinal direction, a longitudinal direction, or MD. Moreover, the direction perpendicular | vertical to the machine axis direction and the thickness direction may be called a horizontal direction, a width direction, or TD.

[Biaxially oriented polyester film]

The biaxially oriented polyester film of the present invention is a film composed of polyester and biaxially oriented. As such a polyester, it is obtained using a polybasic acid or its ester forming derivative, and a polyol or its ester forming derivative. Specific examples of the polybasic acid include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Pyromellitic acid, dimer acid, maleic acid, itaconic acid, and the like. Specific examples of the polyol include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and the like. In this invention, crystalline or semicrystalline polyester obtained from these is preferable. Among these, polyester (polyethylene terephthalate (PET)) mainly containing ethylene terephthalate units or polyester (polyethylene naphthalate (PEN)) mainly containing ethylene naphthalate units can be preferably used. The "main component" shows here that it occupies 80 mol% or more, Preferably it is 90 mol% or more, More preferably, 95 mol% or more of all the repeating units which comprise polyester.

The polyester in this invention may be co-polyester which copolymerized another component in the range in which the effect of this invention is not impaired. As a copolymerization component, a polybasic acid component may be sufficient and a polyol component may be sufficient, for example, the component derived from the said polybasic acid or its ester forming derivative, and the component derived from a polyol or its ester forming derivative is mentioned. These may be used independently and may use 2 or more types. When the amount of copolymerization is too large, the crystallinity tends to be lowered, the heat resistance tends to be lowered, and the refractive index tends to be lowered. Therefore, 10 mol% or less is preferable with respect to 100 mol% of all polybasic acid components.

The polyester in this invention may be a blend body which mixed 2 or more types of polyester in the range in which the effect of this invention is not impaired. Moreover, the blend body which mixed other resin components different from polyester may be sufficient. For example, from a heat resistant viewpoint, it is preferable to blend polyetherimide, a liquid crystal resin, etc. (For example, Unexamined-Japanese-Patent No. 2000-355631, Unexamined-Japanese-Patent No. 2000-141475, Japanese Unexamined Patent Publication). See pp. 11-1568). Moreover, the blend body which added 0.5-5 mol% of polyether imide based on 100 mol% of polyethylene terephthalates can be illustrated, for example.

In the present invention, the polyester constituting the biaxially oriented polyester film is excellent in mechanical properties, heat resistance, dimensional stability, transparency, and the like, and can increase the inhibitory effect of curling, and thus, polyethylene terephthalate and polyethylene Naphthalate is preferred, and polyethylene naphthalate is particularly preferred.

(Polyethylene naphthalate)

Polyethylene naphthalate is polyester whose main polybasic acid component is a naphthalenedicarboxylic acid component, and a main polyol component is an ethylene glycol component. Here, as naphthalenedicarboxylic acid, 2, 6- naphthalenedicarboxylic acid, 2, 7- naphthalenedicarboxylic acid, 1, 5- naphthalenedicarboxylic acid, etc. are mentioned, for example, From the viewpoint of excellent crystallinity and heat resistance, 2,6-naphthalenedicarboxylic acid is preferable. In addition, "main" means here that with respect to 100 mol% of all polybasic acid components, 90 mol% or more in a polybasic acid component is a naphthalenedicarboxylic acid component, and 90 mol% or more in a polyol component is an ethylene glycol component. More preferably, they are 95 mol% or more, respectively.

The polyethylene naphthalate may be a copolymer. In the case of a copolymer, as a copolymerization component, the component derived from the compound which has two ester-forming functional groups in a molecule | numerator can be used. As such a compound, for example, oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4'-diphenyl Dicarboxylic acids such as dicarboxylic acid, phenyl indane dicarboxylic acid, tetralin dicarboxylic acid, decalin dicarboxylic acid, diphenyl ether dicarboxylic acid and the like, p-oxybenzoic acid, p-oxyethoxybenzoic acid Oxycarboxylic acids such as propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane methylene glycol, neopentyl glycol, ethylene oxide adducts of bisphenol sulfone, ethylene oxide adducts of bisphenol A, diethylene Dihydric alcohols such as glycol, polyethylene oxide glycol and the like can be preferably used. Moreover, the aspect by which the naphthalenedicarboxylic acid component from which the coupling | bonding position of carboxylic acid differs with the naphthalenedicarboxylic acid component as a main polybasic acid component is copolymerized is mentioned preferably. Only 1 type may be used for these compounds and 2 or more types may be used for them. Moreover, as a more preferable copolymerization component among these, isophthalic acid, terephthalic acid, 4,4'- diphenyl dicarboxylic acid, 2,7- naphthalenedicarboxylic acid, p-oxybenzoic acid, trimethylene glycol, hexamethylene glycol neo The component derived from the ethylene oxide addition product of pentyl glycol and bisphenol sulfone is mentioned.

The polyester in this invention can be obtained by a conventionally well-known method. For example, a method of directly obtaining a low-polymerization polyester by reaction of dicarboxylic acid and glycol, or a lower alkyl ester of dicarboxylic acid and glycol is a conventionally known transesterification catalyst, for example sodium, potassium, magnesium It can be obtained by a method of carrying out polymerization in the presence of a polymerization catalyst after reacting with one kind or two or more kinds of compounds containing calcium, zinc, strontium, titanium, zirconium, manganese and cobalt. Examples of the polymerization catalyst include antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds represented by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or partial hydrolysis thereof, titanyl ammonium oxalate, And titanium compounds such as titanium oxalate potassium and titanium trisacetylacetonate. When superposing | polymerizing via transesterification, phosphorus compounds, such as trimethyl phosphate, a triethyl phosphate, a tri-n- butyl phosphate, a regular phosphoric acid, are usually added in order to deactivate the transesterification catalyst before a superposition | polymerization reaction. It is preferable that content in the polyester of such a phosphorus compound is 20-100 mass ppm as a phosphorus element from the viewpoint of the thermal stability of polyester.

The polyester may be chipped after melt polymerization, and may be subjected to solid phase polymerization under heating and reduced pressure or in an inert air stream such as nitrogen.

In the present invention, the intrinsic viscosity of the polyester is preferably 0.40 dl / g or more, more preferably 0.40 to 0.90 dl / g. By making intrinsic viscosity into this range, the intensity | strength preferable as a board | substrate for organic electroluminescent illumination is obtained. When intrinsic viscosity is less than 0.40 dl / g, process cutting may be frequent. Moreover, when it is higher than 0.9 dl / g, since melt viscosity is high, melt extrusion becomes difficult and polymerization time is long and it is not economical.

(Film thickness)

The thickness of the biaxially-oriented polyester film of this invention satisfy | fills the following formula.

FT ≥ 0.025

FT / GT ² ≤ 0.25

However, in said formula, FT is thickness (unit: mm) of a biaxially-oriented polyester film, GT is thickness (unit: mm) of the glass plate used in the manufacturing process of a flexible electronics device. This invention finds out that the square of the magnitude | size of the curl of a laminated body, the thickness of a biaxially-oriented polyester film, and the thickness of a glass plate is closely related in this way.

By making a film thickness satisfy | fill the said aspect, the stress which arises between a glass plate and a board | substrate film at the time of cooling of a glass plate-substrate film laminated body can be reduced, and it arises in the electronic circuit formation of the manufacturing process of a flexible electronics device. Curling can be suppressed. If the value of FT / GT ² is too large, curl suppression is insufficient. From such a viewpoint, the value of FT / GT ² becomes like this. Preferably it is 0.24 or less, More preferably, it is 0.21 or less, More preferably, it is 0.17 or less. On the other hand, when the value of FT / GT ² is small, the film thickness tends to be thin and the curl tends to be small. On the other hand, when the film thickness is too thin, wrinkles are easily generated when bonding with the glass plate in the manufacturing process of the flexible electronic device. The handleability tends to be inferior, for example. In addition, the rigid electronic device lacks rigidity, so that failure of the electronic circuit occurs easily during use, or it is easy to disturb the operation of the electronic circuit. From such a viewpoint, film thickness becomes like this. Preferably it is 35 micrometers or more, More preferably, it is 45 micrometers or more, More preferably, it is 48 micrometers or more, Especially preferably, it is 50 micrometers or more.

As described above, the heating curl of the glass plate-substrate film laminate is determined by the relationship between the shrinkage stress of the substrate film during cooling and the rigidity of the glass substrate. Therefore, the higher the rigidity of a glass plate, the curl tends to become smaller. On the other hand, in reality, since the glass plate used for the manufacture of the optical device needs to satisfy other special requirements, it is difficult to greatly change its rigidity (elastic modulus). I can only do it. However, when the thickness of a glass plate is too thick exceeding, for example, 1 mm, the weight becomes heavy, and a problem, such as a handleability fall or productivity fall, arises. Moreover, there exists a possibility that it cannot become applicable to existing general liquid crystal manufacturing facilities. Therefore, the thickness of a glass plate is 0.3-0.7 mm, Preferably it is 0.4-0.7 mm, More preferably, it is the range of 0.5-0.7 mm. And since the glass plate of such thickness is used, the problem of curl arises in a laminated body.

About the glass plate of such thickness, when the said formula is considered, it is necessary to make film thickness 122.5 micrometers or less. And as is clear from the mechanism mentioned above and the said formula, the thinner the film thickness, the smaller the interfacial stress generated at the time of cooling, and the curl can be suppressed. On the contrary, when film thickness is too thick, curl cannot be suppressed. From such a viewpoint, as a film thickness, Preferably it is 117 micrometers or less, More preferably, it is 102 micrometers or less, More preferably, it is 83 micrometers or less, Especially preferably, it is 77 micrometers or less, Most preferably, it is 75 micrometers or less.

(Other film characteristics)

The coefficient of thermal expansion of the biaxially oriented polyester film of the present invention is 25 in any one direction (preferably longitudinal direction) in the film plane and in the direction orthogonal to it in the film plane (preferably horizontal direction). ppm / degrees C or less is preferable. By setting it as such a range, the inhibitory effect of curl can be improved. When the thermal expansion coefficient exceeds 25 ppm / degrees C, the shrinkage stress at the time of cooling becomes large and the suppression effect of a curl falls. From such a viewpoint, More preferably, it is 20 ppm / degrees C or less. In this sense, the smaller the thermal expansion coefficient is, the more preferable. On the other hand, when a draw ratio is raised or molecular orientation is made high, it will become the tendency which the cutting etc. arise easily during manufacture, and there exists a limit. From such a viewpoint, in the case of a biaxially-oriented polyester film, 10 ppm / degreeC is normally a minimum, Preferably it is 15 ppm / degrees C or more. Such a thermal expansion coefficient can be adjusted by controlling the orientation state of molecular chains, and the higher the molecular orientation, the smaller the thermal expansion coefficient.

In the biaxially oriented polyester film of the present invention, the heat shrinkage rate at 200 ° C. for 10 minutes is in any one direction (preferably longitudinal direction) in the film plane and in a direction perpendicular to it in the copper film plane ( Preferably, the transverse direction) is preferably 0.2% to 1.0%. By making such a thermal contraction rate into the said numerical range, the suppression effect of a curl can be heightened. From such a viewpoint, the heat shrinkage ratio is more preferably 0.7 to 1.0%. Such a heat shrinkage rate can be achieved by adjusting the film manufacturing conditions of a film suitably. Moreover, it also becomes easy to achieve by employ | adopting polyethylene naphthalate as polyester.

[Binder layer]

In this invention, 50-100 mass% of thermoplastic resin whose glass transition temperature is 80 degrees C or less on at least one side of a biaxially-oriented polyester film, Preferably it is 70-100 mass%, More preferably, it is 90-100 mass% It is preferable to have a binder layer to contain. By having such a binder layer in the side which bonds a glass plate of a biaxially-oriented polyester film, in the manufacturing process of a flexible electronics device, when a glass plate-substrate film laminated body is heated and cooled, at the time of such a binder layer, The interfacial stress can be absorbed, whereby the effect of suppressing curl can be enhanced.

It is preferable that it is at least 1 sort (s) chosen from the group which consists of a polyester resin, a urethane resin, an acrylic resin, and a vinyl resin as such a thermoplastic resin. In addition, these are preferably water-soluble or water-dispersible from the viewpoint of handling. In this invention, it is preferable that such a thermoplastic resin contains especially polyester resin or both of a polyester resin and an acrylic resin, and can further raise the suppression effect of curl.

The glass transition temperature of the thermoplastic resin which comprises a binder layer is 80 degrees C or less, Preferably it is 75 degrees C or less. Thereby, the suppression effect of curl can be heightened further. When glass transition temperature exceeds 80 degreeC, it will become difficult to absorb the interfacial stress which arises at the time of cooling after heating (at the time of shrinkage) by the binder layer itself deformation, and the suppression effect of curl will become low. Thus, in order to raise the suppression effect of a curl, it is preferable that the glass transition temperature of the thermoplastic resin of a binder layer is low. On the other hand, when the glass transition temperature is lower than room temperature, the film may stick to each other during storage in a rolled state, and there may be a problem such as unstable drawing, so the glass transition temperature is preferably 25. Or more, more preferably 50 or more.

(Polyester resin)

As a polyester resin used preferably as a thermoplastic resin in a binder layer, it satisfy | fills the range of the glass transition temperature mentioned above, and consists of the following polybasic acid component and a polyol component. As the polybasic acid component, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromelli The component derived from a triacid, dimer acid, 5-sodium sulfoisophthalic acid, etc. are mentioned. Copolyester resin is synthesize | combined using 2 or more types of these polybasic acid components. Moreover, as a polyol component, ethylene glycol, 1, 4- butanediol, diethylene glycol, dipropylene glycol, 1, 6- hexanediol, 1, 4- cyclohexane dimethanol, xylene glycol, dimethylol propane, poly ( The component derived from ethylene oxide) glycol, poly (tetramethylene oxide) glycol, bisphenol A, the ethylene oxide of a bisphenol A, or a propylene oxide adduct is mentioned. It is preferable to synthesize | combine a copolyester resin using these polyol components also 2 or more types. In addition, in this invention, it is not limited to these monomers.

It is preferable from the viewpoint of the handleability in forming a binder layer that such polyester resin is soluble or dispersible in water.

(Acrylic resin)

As an acrylic resin used preferably as a thermoplastic resin in a binder layer, glass transition temperature becomes like this. Preferably it is -50-50 degreeC, More preferably, it is -50-25 degreeC. It is preferable that this acrylic resin is soluble or dispersible in water from a viewpoint of the handleability in forming a binder layer.

As a monomer which forms an acrylic resin, epoxy groups, such as an alkyl acrylate, an alkyl methacrylate, 2-hydroxyalkyl acrylate, 2-hydroxyalkyl methacrylate, glycidyl acrylate, glycidyl methacrylate, etc. Acrylic monomer containing acrylate, carboxyl group or salt thereof, acrylic monomer containing amide group, acrylic monomer containing acid anhydride, isocyanates, styrenes, vinyl ethers, vinyltrialkoxysilane, monoalkyl maleate Monomers such as ester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, acrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate and butadiene.

As a thermoplastic resin in a binder layer, when using a polyester resin and an acrylic resin together, these weight content ratios (content of polyester resin: content of acrylic resin) are 1: 9-9: 1, Preferably Is 3: 7-7: 3, More preferably, it is 4: 6-6: 4, and can further raise the suppression effect of curl. Moreover, blocking resistance can be provided.

(Optional component)

In the binder layer, a crosslinking agent such as an oxazoline crosslinking agent such as a polymer having an oxazoline group, a melamine crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent such as a polymer having an oxazoline group, an antistatic agent, a colorant, a surfactant, etc. , Ultraviolet absorbers, lubricants (fillers, waxes) and the like can be added. In particular, by adding a lubricant, the activity and blocking resistance can be further improved. Content of these arbitrary components is 50 mass% or less with respect to 100 mass% of binder layers, Preferably it is 30 mass% or less, More preferably, it is 10 mass% or less.

(Formation method of the binder layer)

The binder layer may be formed by a lamination method, a molten resin coating method, a coextrusion method, or the like, but it is preferable to form the binder layer by a coating method for applying a coating liquid for forming a binder layer from the viewpoint of productivity. Such a coating liquid contains the said thermoplastic resin and the said arbitrary component as needed. In order to improve handleability, it is preferable to use a coating liquid as a form of aqueous coating liquid, such as aqueous solution, aqueous dispersion, or emulsion liquid, using a water-soluble or water-dispersible thermoplastic resin or arbitrary components.

Solid content concentration of a coating liquid is 20 mass% or less normally, Preferably it is 1 mass% or more, It is preferable that it is 10 mass% or less. If this ratio does not satisfy | fill a lower limit, there exists a tendency for applicability | paintability to become low and a binder layer may not be formed uniformly. On the other hand, when the upper limit is exceeded, the stability and coating appearance of the coating liquid may deteriorate. Such a coating layer can be formed in the film manufacturing process of a biaxially-oriented polyester film as mentioned later.

(Young's modulus)

It is preferable that the Young's modulus of a binder layer is 10 GPa or less. By making the Young's modulus of a binder layer into the said numerical range, the suppression effect of a curl can be heightened more. When Young's modulus is too high, there exists a tendency for the inhibitory effect of curl to become low. From such a viewpoint, the Young's modulus of a binder layer becomes like this. More preferably, it is 8 GPa or less, More preferably, it is 6 GPa or less, Especially preferably, it is 5 GPa or less. Thus, in curl suppression, it is preferable that a Young's modulus is low. On the other hand, when Young's modulus is too low, there exists a tendency for inferior in utility, for example, to become easy to scratch a surface in a film manufacturing process and a processing process. From such a viewpoint, it is preferable that a Young's modulus is 2 GPa or more substantially, More preferably, it is 4 GPa or more, Especially preferably, it is 4.5 GPa or more.

Such a Young's modulus can be achieved by adjusting the glass transition temperature of the thermoplastic resin which comprises a binder, or adding the additive which has a plasticizing effect. For example, when the glass transition temperature is made high, the Young's modulus tends to be high.

[Film Production of Biaxially Oriented Polyester Film]

The biaxially-oriented polyester film of this invention can be manufactured by the following method.

A biaxially-oriented polyester film melt-extrudes the polyester mentioned above in the form of a film, for example, it cools and solidifies with a casting drum, and makes it an unstretched film, and makes this unstretched film at Tg- (Tg + 60) degreeC. In the machine axis direction and in the direction perpendicular to the machine axis direction, the film is stretched in the biaxial direction at a stretching ratio of 1.1 to 10 times, preferably 2.5 to 4.0 times, respectively, and (Tm-100) to (Tm-5) ° C. It can obtain by heat-setting for 1 to 100 second at the temperature of. Tg is the glass transition temperature of polyester here, Tm represents melting | fusing point of polyester, respectively.

Stretching can be performed by a method generally used, for example, by a method using a roll or a method using a stenter, and may be simultaneously stretched in the vertical direction and the horizontal direction, and even in the longitudinal direction and the horizontal direction. do.

When the relaxation treatment is carried out after heat fixing, it can be carried out at a temperature of (X-80) to X ° C. X represents a heat setting temperature here. As a method of a relaxation process, it is preferable to use the method of holding both edges with a tenter, narrowing a clip space | interval in a longitudinal direction, and narrowing a rail width in a width direction in an oven. By using such a method, in addition to the heat-resistant dimensional stability in the longitudinal direction, the heat-resistant dimensional stability in the width direction can be easily controlled. The relaxation rate is preferably 1 to 5%.

A binder layer can be apply | coated and formed by the following method, for example.

In the case of sequential stretching, a binder layer can be formed by a method of applying a coating liquid for forming a binder layer to a monoaxially oriented film stretched in one direction, and then stretching in the other direction to heat fix. have. In the case of simultaneous stretching, the binder layer can be formed by the method of apply | coating the coating liquid for forming a binder layer to an unstretched film, extending | stretching in the biaxial direction, and then heat-setting.

As the coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method, etc. can be used individually or in combination. The wet coating amount per film 1 m 2, preferably 0.5 to 20 g, more preferably 1 to 10 g. It is preferable to use a coating liquid as aqueous solution, aqueous dispersion, or emulsion liquid.

[Laminate]

The laminated body which bonded the biaxially-oriented polyester film of this invention and the glass plate of thickness 0.3-0.7 mm used in the manufacturing process of a flexible electronics device, Preferably the 150 mm square sample at 180 degreeC for 30 minutes After heating, it was cooled to room temperature, placed on a horizontal and flat pedestal in the direction in which the curl direction was convex downward, and the rising height from the horizontal plane of the four corners was measured, and the curl height determined as their average value was 0.8 mm or less. to be. The fact that such a value is small means that the curl is suppressed, and by setting the curl height to the above numerical range, problems in forming an electronic circuit can be suppressed in the manufacturing process of the flexible electro device. From such a viewpoint, the curl height is more preferably 0.7 mm or less, still more preferably 0.6 mm or less, and particularly preferably 0.5 mm or less.

Example

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. In addition, each characteristic value was measured with the following method. In addition, the part and% which are related to the mass in an Example mean a mass part and a mass%, respectively, unless there is particular notice.

(1) film thickness, glass plate thickness

It measured by 30 g of needle pressures using the electronic micrometer (brand name "K-312A type" by Anritsu Corporation).

(2) Coefficient of thermal expansion

A film was set in Seiko Instruments Co., Ltd. TMA / SS 120C with a sample width of 3 mm and 15.05 mm between chucks, and the temperature was raised at a temperature increase rate of 10 ° C./min from 30 ° C. to 150 ° C. under a load of 80 g / mm 2. It was measured by. In the obtained temperature dimensional change curve, the thermal expansion coefficient was determined from the inclination of 50 to 100 ° C.

In addition, when Tg of the polyester which comprises a film is less than 110 degreeC, a thermal expansion coefficient is calculated from the inclination of 50- (Tg-10) degreeC in the obtained temperature dimension change curve in consideration of the influence of heat shrinkage of a film, etc. Obtained.

(3) Glass transition temperature

A differential scanning calorimetry device (10 mg) of a sample, for example, a thermoplastic resin (when the sample is a solution or dispersion of a thermoplastic resin, dried at 80 ° C. for 24 hours to produce a dry film, and obtained) (10 mg) TA Instruments 2100 DSC) was used to measure the temperature at a rate of 20 ° C / min.

(4) Young's modulus of binder layer

The coating liquid for forming a binder layer was dried at 80 degreeC for 24 hours, and the dry film was produced. About the obtained dry film sample, Young's modulus was measured using the ultra-micro hardness hardness apparatus and ENT-1100a made from Elionix Corporation. The measurement conditions were 0.49 mN of maximum load, 1.96 μN of data reading input step, 40 msec of data reading input interval, and 1 sec of load holding time when the maximum load was reached. The indenter used was a triangular pyramid (115 °) whose tip was made of diamond. The average of five consecutive measurements per load was determined. In addition, it was calculated | required as 1 kgf = 9.8N.

(5) intrinsic viscosity (η)

The value calculated by the following formula was used from the solution viscosity measured at the temperature of 35 degreeC after melt | dissolving in the phenol: tetrachloroethane mixed solvent of weight ratio 6: 4.

ηsp / C = [η] + K [η] ² C

Here, eta sp = (solution viscosity / solvent viscosity) -1, C is the dissolved polymer weight (g / 100 ml) per 100 ml of solvent, and K is the Huggins constant. In addition, solution viscosity and solvent viscosity were measured using the Ostwald viscometer. A unit is represented by [kV / g].

(6) heat shrinkage

The film samples were given marks at 30 cm intervals, heat treated in an oven set at 200 ° C. for 10 minutes without applying a load, and the gaps between the marks after the heat treatment were measured to determine the thermal shrinkage in the longitudinal and transverse directions of the film. Obtained.

Example 1

(Production of Biaxially Oriented Polyester Film)

Polyethylene-2,6-naphthalenedicarboxylate containing no particles obtained by performing polycondensation reaction after transesterification using naphthalene-2,6-dicarboxylic acid dimethyl and ethylene glycol as monomer raw materials ( Intrinsic viscosity 0.61 dl / g, Tg 120 ° C) was used as the polyester. At this time, manganese acetate tetrahydrate was used as the transesterification catalyst and antimony trioxide was used as the polycondensation catalyst.

After drying the obtained pellet of polyethylene-2,6-naphthalenedicarboxylate at 170 degreeC for 6 hours, it supplied to the extruder hopper, melted at melting temperature of 305 degreeC, and the stainless steel fine wire filter with an average graduation space of 17 micrometers. It filtered, passed through the slit-like die of 3 mm space | interval, and extruded on the rotary cooling drum of surface temperature of 60 degreeC, and quenched and obtained the unstretched film. The unstretched film obtained in this way was preheated at 120 degreeC, and was heated by 900 degreeC IR heater from 15 mm upper direction between the low speed and high speed rolls, and it extended | stretched 3.1 times in the longitudinal direction. Subsequently, the coating liquid (water dispersion, 6 mass% of solid content concentration) for forming the binder layer A which consists of 100 mass% of polyester resins as a thermoplastic resin shown in Table 1 on one side of a film using a roll coater After coating (wet coating amount 7.0 g / m 2), it was fed to a tenter and stretched 3.3 times in the transverse direction at 145 ° C. The obtained biaxially stretched polyester film was heat-fixed at the temperature of 230 degreeC for 40 second, and the biaxially-oriented polyester film of thickness 50micrometer which has a binder layer A of thickness 0.1micrometer was obtained. The 200 degreeC x 10 minute heat shrink rate of the obtained biaxially-oriented polyester film was MD 0.9% and TD 0.8%. Moreover, the thermal expansion coefficients were MD 18 ppm / degrees C and TD 17 ppm / degrees C.

(Preparation of laminate)

Subsequently, the film was cut out to 150 mm in all directions, and the same sized adhesive sheet (Three M make, type 8712, thickness 25 micrometers) was carried out to the glass plate (Eggle XG manufactured by Corning Co., Ltd.) of thickness 0.5mm on all sides 150mm. The laminate was prepared by fixing the binder layer and the adhesive sheet surface in contact.

(Evaluation of Curl)

After heating the obtained glass plate-film laminated body for 30 minutes in 180 degreeC oven, it took out from oven and cooled. This laminated body was placed on a horizontal stage, the height which rises from the horizontal surface of four corners was measured, and those average values were calculated | required and it was set as the curl height. The height was measured by photographing a sample from a horizontal position with a digital camera, enlarging the obtained image, and measuring to 0.1 mm unit. Thus, the curl height of the laminated body obtained is shown in Table 2.

[Examples 2 to 8 and Comparative Examples 1 to 6]

Except having changed the kind of glass thickness, the film thickness, and the binder layer as shown in Table 2, it carried out similarly to Example 1, the biaxially-oriented polyester film was obtained, the laminated body was produced, and the curl was evaluated. Table 2 shows the curl height of the obtained laminate.

As can be seen from Table 2, curling did not occur well in the laminate obtained in Examples 1 to 8 even if the thermal history of 180 ° C was applied.

In addition, in Table 1, the polybasic acid component and polyol component which comprise the polyester resin in each binder layer are as follows.

TA: terephthalic acid component

IA: isophthalic acid component

K2: 5-Na sulfoisophthalic acid component

QA ： 2,6-naphthalenedicarboxylic acid component

EG: ethylene glycol component

BPA: Bisphenol A ethylene oxide adduct component

(Manufacture of Flexible Electronics Devices)

Next, biaxially obtained in the above example as a substrate film using Corning EAGLE XG (thickness 0.5 mm, 320 mm x 400 mm) as a glass plate, and OCA7172 (0.25 mm thickness) manufactured by 3M as an adhesive sheet. Using the oriented polyester film, a laminate of glass plates / adhesive sheets / substrate films was produced.

After heating this laminated body for 30 minutes at the temperature of 180 degreeC, the heat cycle which cools to room temperature at the speed | rate of 20 degree-C / min was repeated 3 times.

A 0.1 mm-thick ITO film was laminated on the substrate after the heat treatment by the sputtering method, and a resist pattern was formed thereon by a conventional method. It etched using it as a mask, the stripe-shaped electronic circuit of 0.1 mm of line width and 0.1 mm of intervals was formed, and the laminated body in which the electronic circuit was formed was obtained. Subsequently, the glass plate and the adhesive sheet were peeled from this laminated body, and the flexible electronic device was obtained.

When the films obtained in Examples 1 to 8 were used, there was no bending or line width unevenness or suppression of the line of the electronic circuit throughout the flexible electronic device, and there was no problem as the electronic circuit.

On the other hand, when the films obtained in Comparative Examples 1-6 were used, the line space of an electronic circuit was not linear but the short circuit error generate | occur | produced especially in the edge part of a flexible electronics device.

Effects of the Invention

According to the present invention, a substrate film is bonded to one surface of a glass plate having a thickness of 0.3 to 0.7 mm to form a laminate, and after the electronic circuit is formed on the substrate film of the laminate, the manufacturing process of the flexible electronic device for peeling the glass plate is performed. WHEREIN: The laminated body used for manufacture of the flexible electronic device in which the curl by the heat processing at the time of electronic circuit formation was suppressed can be provided.

Moreover, according to this invention, in the manufacturing process WHEREIN: The biaxially oriented poly used as the flexible electronics device substrate film in a laminated body which can suppress the curl of the laminated body by the heat processing at the time of electronic circuit formation. Ester films may be provided.

Moreover, according to this invention, the flexible electronics device using the said laminated body and its manufacturing method can be provided.

Since the generation of curl is suppressed in the manufacturing process of the flexible electronic device obtained using the laminated body of this invention or a biaxially-oriented polyester film, formation of an electronic circuit is easy and it is possible to reduce the error of an electronic circuit. Can be.

Industrial availability

This invention is useful for manufacture of the flexible electronic device which used the glass plate and board | substrate film of thickness 0.3-0.7 mm.

Claims (8)

After bonding a substrate film to one side of a glass plate having a thickness of 0.3 to 0.7 mm to form a laminate, and forming an electronic circuit on the substrate film of the laminate, the flexible electronic device manufactured by peeling the glass plate. The laminated body for manufacture of the flexible electronics device which has a biaxially-oriented polyester film in which the film thickness satisfy | fills following formula as a board | substrate film on the single side | surface of the glass plate of thickness 0.3-0.7 mm as a laminated body used in manufacture.
FT ≥ 0.025
FT / GT ² ≤ 0.25
(However, in the above formula, FT is the film thickness (unit: mm), GT is the thickness of the glass plate (unit: mm)) The method of claim 1,
The laminated body for flexible electronics device manufacture whose polyester which comprises a biaxially-oriented polyester film is polyethylene naphthalate. 3. The method according to claim 1 or 2,
The laminated body for flexible electronics device manufacture whose thermal contraction rate after heat-processing the biaxially-oriented polyester film for 10 minutes at 200 degreeC is 0.2 to 1.0%. The method according to any one of claims 1 to 3,
The laminated body for flexible electronics device manufacture which has a binder layer in which a biaxially-oriented polyester film contains 50-100 mass% of thermoplastic resin whose glass transition temperature is 80 degrees C or less on at least one side. 5. The method of claim 4,
The laminated body for manufacturing flexible electronics devices whose Young's modulus of a binder layer is 2-10 GPa. The biaxially-oriented polyester film for flexible electronics device substrate films used as a board | substrate film in the laminated body for flexible electronics device manufacture of any one of Claims 1-5. The biaxially-oriented polyester film is bonded together as a board | substrate film to the single side | surface of the glass plate of thickness 0.3-0.7 mm, the laminated body for manufacturing the flexible electronics device as described in any one of Claims 1-5 is formed, and then the board | substrate The flexible electronics device manufactured by peeling a glass plate after forming an electronic circuit on a film. The biaxially-oriented polyester film is bonded together as a board | substrate film to the single side | surface of the glass plate of thickness 0.3-0.7 mm, the laminated body for manufacturing the flexible electronics device as described in any one of Claims 1-5 is formed, and then the board | substrate The manufacturing method of the flexible electronics device which peels a glass plate after forming an electronic circuit on a film.