TWI659832B - Complex - Google Patents

Abstract

An object of the present invention is to provide a composite body that is less prone to cracking when a tensile stress is applied to a glass substrate having a minute crack on the surface. The invention relates to a composite in which the resin of the resin layer penetrates into at least a part of the interior of the micro-cracks, and the ratio of the depth d _f of the resin from the surface of the glass substrate to the depth d of the micro-cracks and the fracture of the resin layer The product of the elongation TE (%) and the undulating stress σ _S (MPa) of the resin layer is 400 MPa ·% or more, and the tensile elastic modulus of the resin layer is 1.0 GPa or more.

Description

Complex

The present invention relates to a composite body, in particular to a composite body in which a resin penetrates to a specific depth inside a minute crack on the surface of a glass substrate.

As a substrate of an electronic device such as an image display panel, a solar cell, and a thin film secondary battery, a composite sheet having a glass sheet and a resin layer bonded to the glass sheet has been proposed (for example, refer to Patent Document 1). When the glass sheet contained in the composite sheet is bent and deformed with a specific curvature radius, and the tensile stress is generated on the main surface of the glass sheet combined with the resin layer, the tensile stress is reduced due to the presence of the resin layer. small. This can suppress breakage of the glass sheet.

[Prior technical literature] [Patent Literature]

Patent Document 1: International Publication No. 2012/166343

On the other hand, various processes, such as a washing process, a grinding process, and a cutting process, are usually performed on a glass substrate, and a micro crack is formed in the surface of a glass substrate at this time.

The present inventors, referring to the description in Patent Document 1, formed a resin layer on a glass substrate having minute cracks formed on the surface after a specific treatment, and evaluated the characteristics of the composite. As a result, they found that if a tensile stress is applied to the glass substrate, There are cases where it is easy to break.

In view of the above-mentioned actual situation, the present invention aims to provide an A micro-cracked glass substrate is less likely to break when a tensile stress is applied.

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, the first aspect of the present invention is a composite body comprising a glass substrate having microcracks on its surface, and a resin layer disposed on the glass substrate, and the resin of the resin layer penetrates into at least the inside of the microcracks. In part, the ratio of the depth d _f of the resin from the surface of the glass substrate to the depth d of the minute cracks (d _f / d), the elongation at break TE (%) with the resin layer, and the yield of the resin layer The product of the stress σ _S (MPa) (ratio (d _f / d) × elongation at break TE × falling stress σ _S ) is 400 MPa ·% or more, and the tensile elastic modulus E _resin of the resin layer is 1.0 GPa or more.

In the first aspect, the average thickness of the glass substrate is preferably 10 to 200 μm.

In the first aspect, the average thickness of the resin layer is preferably 10 to 100 μm.

In the first aspect, the resin layer preferably contains polyimide.

A second aspect of the present invention is an electronic device including the composite as the first aspect, and an element formed on a glass substrate of the composite.

According to the present invention, it is possible to provide a composite body that is less prone to cracking when a tensile stress is applied to a glass substrate having minute cracks on its surface.

2‧‧‧ complex

4‧‧‧ glass substrate

6‧‧‧ resin layer

8‧‧‧ tiny crack

8a‧‧‧ linear tiny crack

8b‧‧‧point tiny cracks

10‧‧‧ Bending test device

14‧‧‧Upper support plate

14a‧‧‧Support surface of upper support plate

16‧‧‧ underside support plate

16a‧‧‧ Support surface of the lower support plate

17‧‧‧ Stop

18‧‧‧test sheet

70‧‧‧Organic EL Panel (OLED)

71‧‧‧Organic EL element

72‧‧‧pixel electrode

74‧‧‧ organic layer

76‧‧‧ counter electrode

78‧‧‧sealing plate

80‧‧‧LCD panel

82‧‧‧TFT substrate

83‧‧‧TFT element

84‧‧‧CF substrate

85‧‧‧color filter element

86‧‧‧LCD layer

90‧‧‧ solar battery

91‧‧‧solar cell element

92‧‧‧ transparent electrode

94‧‧‧ silicon layer

96‧‧‧Reflective electrode

98‧‧‧sealing plate

100‧‧‧ thin film secondary battery

101‧‧‧ thin film secondary battery element

102‧‧‧Transparent electrode

104‧‧‧electrolyte layer

106‧‧‧Current collector

108‧‧‧Sealing layer

109‧‧‧Sealing plate

110‧‧‧electronic paper

111‧‧‧Electronic paper components

112‧‧‧TFT layer

114‧‧‧ Contains layers of electrical media

116‧‧‧Transparent electrode

118‧‧‧Front panel

d‧‧‧depth of tiny cracks

d _f ‧‧‧ depth of resin from glass substrate surface

D‧‧‧ The distance between the support surface of the upper support plate and the support surface of the lower support plate

W‧‧‧Width of micro cracks

FIG. 1 is a cross-sectional view showing one embodiment of the composite of the present invention.

FIG. 2 is a plan view of a glass substrate having minute cracks.

3 is a cross-sectional view showing a structure of an organic EL panel according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a structure of a liquid crystal panel according to an embodiment of the present invention.

Fig. 5 is a sectional view showing the structure of a solar cell according to an embodiment of the present invention.

Fig. 6 is a sectional view showing the structure of a thin film secondary battery according to an embodiment of the present invention; Illustration.

Fig. 7 is a sectional view showing the structure of an electronic paper according to an embodiment of the present invention.

FIG. 8 is a schematic diagram showing a bending test apparatus for detecting the average breaking strength of a glass substrate and a composite according to an embodiment of the present invention.

FIG. 9 (A) and FIG. 9 (B) are diagrams obtained by causing fluorescein to adsorb on the surface of a glass substrate having micro-cracks and damaging the glass substrate, and observing the broken surface with an optical microscope (FIG. 9 (A) ) And a diagram obtained by observation with a fluorescence microscope (FIG. 9 (B)).

Embodiments for implementing the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same or corresponding symbols, and descriptions thereof are omitted. Moreover, the drawing in the present invention is a schematic drawing, and the thickness relationship or positional relationship of each layer may not be consistent with the real thing. In addition, in this specification, "weight%" and "mass%" have the same meaning.

As one of the characteristics of the composite of the present invention, the characteristics of the resin layer (elongation at break, yield stress, tensile modulus of elasticity) are controlled, and the resin in the resin layer penetrates into the micro cracks of the glass substrate Specific depth. It is thought that the reason why the glass substrate is easily broken is the existence of minute cracks on the glass surface, and it is presumed that when the stress is applied to the glass, the minute cracks greatly extend and cause cracks. Therefore, as described above, a desired effect can be obtained by penetrating a resin exhibiting specific characteristics into the interior of a minute crack.

FIG. 1 is a schematic sectional view of an example of a composite body of the present invention.

The composite 2 includes a glass substrate 4 and a resin layer 6 disposed on the glass substrate 4. There is a micro crack 8 on the surface of the glass substrate 4 on the resin layer 6 side, and the resin in the resin layer 6 penetrates to at least a part of the interior of the micro crack 8.

The composite 2 may be used as a substrate for an electronic device such as an image display panel, a solar cell, or a thin film secondary battery, or may be used for forming various elements. The composite body 2 may be a roll wound on a roll core, or may be a manufacturer for an electronic device performed by a roll-to-roll method.

Moreover, in FIG. 1, the resin layer 6 is provided only on one side of the glass substrate 4, The glass substrate 4 has resin layers 6 on both sides. The two resin layers 6 disposed across the glass substrate 4 may have the same thickness or different thicknesses, may have the same physical properties (tensile elastic modulus, thermal expansion coefficient, etc.) or may have different physical properties.

First, the glass substrate 4 and the resin layer 6 constituting the composite 2 will be described in detail below.

<Glass substrate>

The glass of the glass substrate 4 can be various, and examples thereof include soda-lime glass and alkali-free glass.

The average thickness of the glass substrate 4 is not particularly limited, but is preferably 200 μm or less. When the average thickness of the glass substrate 4 is 200 μm or less, the glass substrate 4 can be wound into a spiral shape to form a glass roll.

The average thickness of the glass substrate 4 is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. The average thickness of the glass substrate 4 is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 5 μm or more, and even more preferably 10 μm or more.

The above average thickness is a value obtained by measuring the thickness of the glass substrate 4 at an arbitrary 10 points or more, and averaging these values.

The thickness deviation in the width direction of the glass substrate 4 is preferably 5 μm or less. The "thickness deviation" means a deviation from the average thickness. If the thickness deviation in the width direction of the glass substrate 4 is 5 μm or less, the stress on the glass substrate 4 when the composite body 2 is deformed during bending is more uniform, and the damage of the glass substrate 4 can be reduced. Moreover, the thickness deviation in the length direction of the glass substrate 4 is generally smaller than the thickness deviation in the width direction of the glass substrate 4. The thickness deviation in the width direction of the glass substrate 4 is more preferably 3 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less. The thickness deviation in the width direction of the glass substrate 4 is obtained by measuring the uneven shape of the front and back surfaces of the glass substrate 4 with a laser displacement meter, respectively.

The glass substrate 4 may have a strip shape, and the width of the glass substrate 4 may be 100 mm or more. When the width of the glass substrate 4 is 100 mm or more, the electronic assembly by the roll-to-roll method In the manufacturing steps, the tensile force applied to the composite 2 may become uneven in the width direction, and the tensile stress may be concentrated on a part of the glass substrate 4. In the above case, the effect of this embodiment (the effect of reducing the breakage of the glass substrate 4) is remarkably exhibited.

The method for manufacturing the glass substrate 4 may be any of a float method, a melting method, and a retraction method. In the case of the float method, the molten glass is flowed on the molten tin in the bath to be formed into a strip shape. After the formed glass is slowly cooled, the cooled glass is cut to a desired size. In the case of the melting method, the molten glass overflowing from the groove-shaped member is merged at the lower end of the groove-shaped member and formed into a strip shape. After the formed glass is slowly cooled, the cooled glass is cut to the required size . In the case of the retraction method, the glass substrate is softened by heat and stretched to a desired thickness, and the stretched glass substrate is cured.

There are minute cracks 8 on the surface of the glass substrate 4. The micro-cracks 8 are generated during various processes (cleaning process, polishing process, cutting process, etc.) when manufacturing a glass substrate, or during operations such as transporting a glass substrate. The shape of the micro-cracks 8 is not particularly limited. For example, as shown in FIG. 2 in a plan view of the glass substrate 4 having micro-cracks, for example, a groove-shaped concave portion 8a or a dot-shaped concave portion 8b can be cited. .

The minute cracks 8 mainly refer to cracks (damages) below a minute size level.

The depth d of the micro-cracks 8 is not particularly limited. The range detectable by an electron microscope or the like is usually 0.1 μm or more, and more preferably 1.0 μm or more. The upper limit is not particularly limited, but it is usually 30 μm or less, and in most cases, 15 μm or less.

The width W of the micro-cracks 8 is not particularly limited, and the range detectable by an electron microscope or the like is usually 1 nm or more, and in most cases, 10 nm or more. The upper limit is not particularly limited, but it is usually 100 μm or less, and more often 10 μm or less.

Examples of the method for measuring the depth d and the width W of the micro-cracks 8 include a method of cutting the composite 2 and observing the cut surface with an electron microscope.

<Resin layer>

The resin layer 6 is a layer disposed on the glass substrate 4, and functions as a reinforcing layer that reinforces the easily broken glass substrate 4.

The relationship between the resin layer 6 and the above-mentioned glass substrate 4 satisfies the following formula (1).

Formula (1): (ratio (d _f / d)) × (breaking elongation TE of the resin layer) × (falling stress σ _{S of the} resin layer) ≧ 400MPa‧%

Hereinafter, each item in the formula will be described in detail first.

As shown in FIG. 1, the resin in the resin layer 6 penetrates (fills in) a part of the area inside the micro-crack 8. The magnitude of the ratio (d _f / d) of the depth d _f (filling depth) of the resin from the surface of the glass substrate 4 to the depth d of the micro-cracks (the embedding ratio of the resin in the depth direction of the micro-cracks) should satisfy the above formula ( The relationship of 1) is not particularly limited. As far as the composite body is less likely to break (hereinafter also referred to as "the aspect of the present invention having more excellent effects"), it is preferably 0.01 or more, and more preferably 0.05 or more. It is preferably 0.1 or more. The upper limit is not particularly limited, and since the depth d _{f is} not larger than the depth d of the minute cracks, it is 1 or less. The above-mentioned depth of penetration d _f represents the deepest position of the resin that penetrates into the interior of the micro-cracks based on the surface of the glass substrate 4.

The above ratio (d _f / d) is an average value, that is, observing more than 10 micro cracks, measuring the depth d and the depth d _f of each micro crack, calculating the ratio (d _f / d) of each micro crack, and The calculated ratio (d _f / d) of each minute crack is a value obtained by arithmetic average.

The above-mentioned depth d and depth d _f are obtained by directly observing the starting point of the damage with an optical microscope after performing the damage test of the composite. In addition, according to the basic formula of failure mechanics ("Ceramic Destruction" P68), theoretical values can also be obtained from the failure stress and stress intensity factor, and the correctness of the above values can be confirmed. Further, regarding the depth d _f , the pigment is dispersed in the resin to be coated in advance, whereby the starting point of the failure after the failure test can be observed with a fluorescence microscope, and its size can be measured and compared with the depth d. Here, the pigment is not particularly limited, and fluorescein or a derivative thereof is preferred.

In the case of resin liquids with poor pigment dispersibility, uniform viscosity can be used. The water-soluble resin is used as a resin for observation. By making the viscosity of the resin layer-forming composition actually used to form the resin layer consistent with the viscosity of the evaluation composition containing the above-mentioned observation resin and pigment, the evaluation composition penetrates into the micro-cracks at the depth d. The degree is the same as when the composition for forming a resin layer is used. Here, the water-soluble resin refers to polyvinyl alcohol (PVA), hydroxycellulose (HEC), and the like. The depth d can also be obtained by adsorbing the pigment on the inner surface of the micro-crack and observing the starting point of the failure after the failure test with a fluorescent microscope.

In addition, as an example, FIG. 9 (A) and FIG. 9 (B) disclose the use of the fracture surface near the destruction starting point of the glass substrate after the destruction test is performed by adsorbing fluorescein to the surface of the glass substrate having microcracks. Photographs obtained by observation with an optical microscope and a fluorescent microscope. FIG. 9 (A) is an observation diagram under an optical microscope, and FIG. 9 (B) is an observation diagram under a fluorescent microscope. The arrows in the figure indicate the thickness direction of the glass substrate. If you compare the two, you can see on one of the surfaces in Figure 9 (B) (the surface on the lower side of the glass substrate in the figure) that the fluorescent light originated from the fluorescein adsorbed inside the micro-crack, from the distance glass The depth d of the fluorescent region on the substrate surface can be calculated. As described above, a pigment (for example, luciferin) may be dispersed in the resin to be coated, and the cross-section of the glass substrate after the breaking test may be observed in the same manner as in FIG. 9 (B) to observe the above-mentioned depth. d _f .

The size of the elongation at break TE (%) of the resin layer 6 is not particularly limited as long as it satisfies the relationship of the above formula (1). In terms of the effect of the present invention, it is more preferably 20% or more, more preferably Over 40%.

The method for measuring the elongation at break TE (%) is based on ASTM D882-12.

The magnitude of the undulating stress σ _S (MPa) of the resin layer 6 is not particularly limited as long as it satisfies the relationship of the above formula (1). In terms of the effect of the present invention, it is preferably 50 MPa or more, and more preferably 100 MPa. the above.

The method for measuring the yield stress σ _S is based on JIS-C-2151: 2006.

The above formula (1) means that the product of the above ratio (d _f / d), the elongation at break TE of the resin layer 6, and the undulating stress σ _S of the resin layer 6 is 400 MPa‧% (N / mm ² ‧%) or more . Among them, as far as the effect of the present invention is more excellent, the left side of the above formula (1) ((ratio (d _f / d)) × (elongation at break of the resin layer TE) × (residual stress of the resin layer σ _S )) Is preferably 450 MPa‧% or more, and more preferably 500 MPa‧% or more. The upper limit is not particularly limited, but it is usually below 8000 MPa‧%, and more often below 2,000 MPa‧%.

As described above, the main reason for the cracking of the glass substrate 4 is that stress is concentrated on the small cracks 8 existing on the surface of the glass substrate 4 and the glass substrate 4 is easily broken. The present inventors have found that: by so formed may exhibit an elongation at break TE and specific yield stress σ _S of the resin layer of the resin to small cracks deep 6 8 inside of a certain depth, i.e., by satisfying the relationship of formula (1) of It can suppress the stress in the direction indicated by the hollow arrow in FIG. 1 to further extend the rupture of the micro-crack 8.

More specifically, as described above, the reason for the cracking of the glass substrate is that the stress is concentrated in the micro-cracks, but when the resin penetrates (embeds) into the micro-cracks, the energy applied to the micro-cracks is distributed according to the depth of penetration To resin. At this time, the amount of work done by the resin is expressed by the following formula (X).

In formula (X), W ′ represents the work done by the resin embedded in the micro-crack, α represents the embedding rate of the resin in the depth direction of the micro-crack, d represents the depth of the micro-crack, and σ represents the undulation Stress, ε represents the elongation at break of the resin.

In the above variables, d (the depth of the minute cracks) corresponds to the deepest minute cracks corresponding to the lowest strength of the glass after a certain step. If the glass substrates of the same batch have no large changes, they can be regarded as approximately constant. In this way, the amount of work W 'depends on α, σ and ε. The inventors have found that if the product of the three parameters is a specific value, the glass substrate is less likely to crack.

In particular, the larger the elongation at break TE of the resin layer 6, the wider the allowable stress range of the resin inside the micro-cracks until the fracture. In addition, the larger the undulation stress σ _{S of} the resin layer 6 is, the wider the allowable stress range of the resin inside the micro-crack until the undulation is.

The tensile elastic modulus E _resin of the resin layer 6 is 1.0 GPa or more. In terms of the effect of the present invention being more excellent, it is preferably 1.5 GPa or more, and more preferably 2.0 GPa or more. The upper limit is not particularly limited, but it is usually 15 GPa or less, and in most cases, 10 GPa or less.

The method for measuring the tensile elastic modulus E _resin is based on JIS-C-2151 (2006).

The average thickness of the resin layer 6 is not particularly limited, but is preferably 100 μm or less. When the average thickness of the resin layer 6 is 100 μm or less, the flexibility of the composite 2 can be sufficiently ensured. In addition, if the average thickness of the resin layer 6 is 100 μm or less, warpage due to a difference in thermal expansion coefficient between the resin and glass can be suppressed. The average thickness of the resin layer 6 is preferably 90 μm or less, and more preferably 75 μm or less. The average thickness of the resin layer 6 is more preferably 0.5 μm or more, more preferably 1 μm or more, and still more preferably 10 μm or more, in terms of the effect of the present invention.

The average thickness is a value obtained by measuring the thickness of the resin layer 6 at an arbitrary 10 points or more, and averaging these values.

The resin layer 6 may be formed only of a resin, for example. The resin layer 6 may be formed of a resin-containing material, and may be formed of, for example, a resin and a filler.

Examples of the filler include fibrous, or plate-like, scaly, granular, irregular, broken, and other non-fibrous filling profiles. Specific examples include glass fiber and PAN (Polyacrylonitrile, polyacrylonitrile). Carbon fibers such as carbon fibers, stainless steel fibers, aluminum fibers or brass fibers, organic fibers such as aromatic polyamide fibers, gypsum fibers, ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, and silicon dioxide Fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, barium titanate Whiskers, aluminum borate whiskers, silicon nitride whiskers, mica, talc, kaolin, silicon dioxide, calcium carbonate, glass beads, glass flakes, glass microspheres, clay, molybdenum disulfide, wollastonite, titanium oxide, Zinc oxide, calcium polyphosphate, metal powder, metal flake, metal strip, metal oxide, carbon powder, graphite, carbon black, scaly carbon, nano carbon tube, etc. Specific examples of the metal species of metal powder, metal foil, and metal strip include silver, nickel, copper, zinc, aluminum, stainless steel, iron, brass, chromium, and tin. The type of glass fiber or carbon fiber is not particularly limited as long as it is generally used for resin reinforcement. For example, it can be selected from long-fiber or short-fiber cut strand fibers, ground fibers, and the like. The resin layer 6 may be made of a woven fabric, a non-woven fabric, or the like impregnated with a resin.

The resin of the resin layer 6 can be various, for example, any of a thermoplastic resin and a thermosetting resin can be used.

Examples of the thermosetting resin include polyimide (PI) and epoxy resin (EP). As the thermoplastic resin, for example, polyamidoamine (PA), polyamidoimine (PAI), polyetheretherketone (PEEK), polybenzimidazole (PBI), liquid crystal polymer (LCP), polyparaphenylene can be used. Ethylene diformate (PET), polyethylene naphthalate (PEN), polyether fluorene (PES), cyclic polyolefin (COP), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene Ethylene (PE), polypropylene (PP), acrylic resin (PMMA (PolymethylMethacrylate, polymethylmethacrylate)), urethane (PU), and the like.

The resin layer 6 may be formed of a photocurable resin, or may be a copolymer or a mixture. The manufacturing steps of the electronic device by the roll-to-roll method sometimes include a step accompanied by a heat treatment, and the heat-resistant temperature (continuous use temperature) of the resin is preferably 100 ° C or higher. Examples of the resin having a heat-resistant temperature of 100 ° C or higher include polyimide (PI), epoxy resin (EP), polyimide (PA), polyimide (PAI), and polyetheretherketone. (PEEK), polybenzimidazole (PBI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether fluorene (PES), cyclic polyolefin (COP), Polycarbonate (PC), polyvinyl chloride (PVC), acrylic resin (PMMA), urethane (PU), etc.

Among these, as the effect of the present invention is more excellent, as the resin in the resin layer 6, polyimide and epoxy resin are preferable, and polyimide is more preferable.

The structure of the polyfluoreneimide is not particularly limited, and it is preferably a repeating unit including a residue (X) having a tetracarboxylic acid type and a residue (A) having a diamine type represented by the following formula (I). In addition, the polyfluorene imide preferably contains a repeating unit represented by formula (I) as a main component (preferably 95 mol% or more with respect to all repeating units), and may also include other repeating units other than ( (For example, the repeating unit represented by Formula (2-1) or (2-2) mentioned later).

In addition, the residue (X) of the tetracarboxylic acid means a tetracarboxylic acid residue obtained by removing a carboxyl group from a tetracarboxylic acid, and the residue (A) of a diamine means a residue obtained by removing an amine group from a diamine. Diamine residue.

In formula (I), X represents a tetracarboxylic acid residue obtained by removing a carboxyl group from a tetracarboxylic acid, and A represents a diamine residue obtained by removing an amine group from a diamine.

In formula (I), X represents a tetracarboxylic acid residue obtained by removing a carboxyl group from a tetracarboxylic acid, and preferably contains at least 1 selected from the group consisting of the groups represented by the following formulae (X1) to (X4) Seed basis. Among them, as far as the effect of the present invention is more excellent, it is more preferably 50 mol% or more (preferably 80 to 100 mol%) of the total number of X, which is selected from the following formulae (X1) to (X4) At least one type of group in the group represented. It is further preferred that the substantially total number (100 mol%) of the total number of X is selected from the group consisting of the bases represented by the following formulae (X1) to (X4) At least one base in the group.

In addition, A represents a diamine residue obtained by removing an amine group from a diamine, and preferably contains at least one group selected from the group consisting of the groups represented by the following formulae (A1) to (A8). Among them, in terms of more excellent effects of the present invention, it is more preferably 50 mol% or more (preferably 80 to 100 mol%) of the total number of A, which is selected from the following formulae (A1) to (A8) At least one type of group in the group represented. Furthermore, it is preferable that the substantially total number (100 mol%) of the total number of A includes at least one type selected from the group consisting of the following formulae (A1) to (A8).

Furthermore, in terms of the effect of the present invention being more excellent, it is preferable that 80 to 100 mole% of the total number of X is selected from the group consisting of the bases represented by the following formulae (X1) to (X4). At least one kind of base, and 80 to 100 mole% of the total number of A includes at least one kind selected from the group consisting of the bases represented by the following formulae (A1) to (A8), and more preferably X Substantially all of the total (100 mole%) includes at least one kind of base selected from the group consisting of the bases represented by the following formulae (X1) to (X4), and substantially all of the total of A (100 moles) Ear%) contains at least one type of group selected from the group consisting of the groups represented by the following formulae (A1) to (A8).

Among these, in terms of more excellent effects of the present invention, X is preferably a base represented by formula (X1) and a base represented by formula (X4), and more preferably a base represented by formula (X1).

In addition, in terms of more excellent effects of the present invention, A is preferably a base represented by formula (A1) and a base represented by formula (A6), and more preferably a base represented by formula (A1).

As a polyimide containing a preferable combination of the bases represented by the formulas (X1) to (X4) and the bases represented by the formulas (A1) to (A8), preferably, X is the compound represented by the formula (X1) Polyfluoreneimine 1 having a group represented by Formula (A1) and A being a polyimide 2 having a group represented by Formula (X4) and A being a group represented by Formula (A6). In the case of polyimide 1, heat resistance is more excellent. In the case of polyimide 2, it is preferable in terms of colorless transparency.

The repeating number (n) of the repeating unit represented by the above-mentioned formula (I) in the polyimide is not particularly limited, and is preferably an integer of 2 or more. In terms of the effect of the present invention being more excellent, it is preferably 10 ~ 10000, more preferably 15 ~ 1000.

The polyfluoreneimide may include, as long as the heat resistance is not impaired, one or more types of residues (X) selected from the group consisting of the groups exemplified below as tetracarboxylic acids. In addition, two or more types of bases exemplified below may be included.

[Chemical 3]

Moreover, the said polyfluoreneimide may contain the residue (A) which is one or more types chosen from the group which consists of a base which is illustrated below as a diamine in the range which does not impair heat resistance. In addition, two or more types of bases exemplified below may be included.

[Chemical 4]

The resin layer 6 only needs to cover a portion where cracking of the glass substrate 4 is to be suppressed, and may be in a form of covering at least a part of one main surface of the resin layer 6. The resin layer 6 preferably covers the entire main surface of one of the glass substrates 4. In addition, the resin layer 6 may protrude from one of the main surfaces of the glass substrate 4.

The method for producing the resin layer 6 is not particularly limited, and the optimum conditions are appropriately selected according to the materials used. In terms of the effect of the present invention being more excellent, a liquid resin composition can be applied to the glass substrate 4 A method of curing the resin to form the resin layer 6.

In addition, the manufacturing method when manufacturing the resin layer (polyimide resin layer) containing the said polyfluorene imine is not specifically limited, It is preferable to use the polyfluorene which is represented by said Formula (I) by thermosetting. The form of curable resin of imine resin.

Hereinafter, a preferred embodiment of a method for producing a polyimide resin layer will be described in detail. Bright. This manufacturing method preferably has the following steps (1) and (2).

Step (1): A step of applying a curable resin that becomes a polyimide resin represented by the above formula (I) by thermal curing onto a glass substrate 4 to obtain a coating film

Step (2): A step of applying a heat treatment to the coating film to form a polyimide resin layer

The procedures of each step are described in detail below.

(Step (1): Coating film forming step)

Step (1) is a step of applying a curable resin which becomes a polyimide resin having a repeating unit represented by the above formula (I) by thermosetting onto a glass substrate 4 to obtain a coating film.

In addition, the curable resin preferably contains polyamine acid obtained by reacting a tetracarboxylic dianhydride with a diamine, and at least a part of the tetracarboxylic dianhydride includes a member selected from the following formulae (Y1) to (Y4) At least one type of tetracarboxylic dianhydride in the group consisting of the compounds represented, and at least a part of the diamines includes at least one selected from the group consisting of compounds represented by the following formulae (B1) to (B8) 1 type of diamine.

The polyamic acid is generally represented by a structural formula including a repeating unit represented by the following formula (2-1) and / or formula (2-2). Furthermore, in the formulas (2-1) and (2-2), the definitions of X and A have the same meanings as the definitions of X and A in the formula (I), respectively.

The reaction conditions of the tetracarboxylic dianhydride and diamine are not particularly limited, and in terms of efficient synthesis of polyamidic acid, it is preferably -30 to 70 ° C (preferably -20 to 40 ° C) ).

The mixing ratio of tetracarboxylic dianhydride and diamines is not particularly limited, and examples include: preferably 0.66 to 1.5 moles, more preferably 0.9 to 1.1 moles, and more preferably 1 mole to the diamines. It is preferably 0.97 to 1.03 mole of tetracarboxylic dianhydride to react with it.

In the reaction of tetracarboxylic dianhydride with diamines, an organic solvent may be used as required. The type of the organic solvent used is not particularly limited, and for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramidine, tetramethylenephosphonium, dimethylphosphonium, m-formyl Phenol, phenol, p-chlorophenol, 2-chloro-4-hydroxytoluene, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diamine Alkane, γ-butyrolactone, dioxolane, cyclohexanone, cyclopentanone, and the like may be used in combination of two or more kinds.

In the above-mentioned reaction, other tetracarboxylic dianhydrides other than the tetracarboxylic dianhydride selected from the group consisting of the compounds represented by the formulae (Y1) to (Y4) may be used in combination as necessary.

In the above reaction, other diamines other than the diamines selected from the group consisting of the compounds represented by the formulae (B1) to (B8) may be used in combination when necessary.

In addition, as the curable resin used in this step, a polycarboxylic acid obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine may be used, and a tetracarboxylic dianhydride capable of reacting with polyamino acid may be added. Or diamines. If tetracarboxylic dianhydride or diamine is added in addition to the polyamic acid, two or more polyamic acids having a repeating unit represented by the formula (2-1) or the formula (2-2) can be made. The molecules are bonded via tetracarboxylic dianhydride or diamine.

In the case where polyamic acid has an amine group at the terminal, tetracarboxylic dianhydride may be added, and the carboxyl group may be added in a manner of 0.9 to 1.1 mol relative to 1 mol of polyamic acid. When the polyamino acid has a carboxyl group at the terminal, a diamine may be added, and the amine group may be added in a manner of 0.9 to 1.1 mol relative to 1 mol of the polyamino acid. Furthermore, when polyamic acid has a carboxyl group at the terminal, an acid terminal may be obtained by adding water or an arbitrary alcohol to open the terminal acid anhydride group.

The tetracarboxylic dianhydride added later is more preferably a compound represented by the formulae (Y1) to (Y4). The diamines to be added later are preferably diamines having an aromatic ring, and more preferably compounds represented by the formulae (B1) to (B8).

When tetracarboxylic dianhydrides or diamines are subsequently added, the degree of polymerization (n) of the polyamic acid having a repeating unit represented by formula (2-1) or formula (2-2) is preferably 1 ~ 20. If polymerization When the degree (n) is within this range, even if the polyamic acid concentration in the curable resin solution is 30% by mass or more, the solution of the curable resin can be brought into a low viscosity state.

In this step, components other than the curable resin may be used.

For example, a solvent can be used. More specifically, the curable resin can be dissolved in a solvent and used in the form of a solution (curable resin solution) of the curable resin. As a solvent, the organic solvent is preferable especially from the point of the solubility of a polyamic acid. Examples of the organic solvent used include organic solvents used in the above reaction.

When an organic solvent is contained in the curable resin solution, the content of the organic solvent is not particularly limited as long as it can adjust the thickness of the coating film and have good coating properties. Generally speaking, it is relative to curing The total mass of the resin solution is preferably 5 to 95% by mass, and more preferably 10 to 90% by mass.

In addition, a dehydrating agent or a dehydrating closed-loop catalyst for promoting dehydration and closing of the polyamic acid may be used in combination as necessary. For example, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. Further, as the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, trimethylpyridine, dimethylpyridine, and triethylamine can be used.

A method of applying a curable resin (or a curable resin solution) on the surface of the glass substrate is not particularly limited, and a known method can be used. Examples include spray coating method, die coating method, spin coating method, dip coating method, roll coating method, bar coating method, screen printing method, and gravure coating method.

The thickness of the coating film obtained by the above-mentioned treatment is not particularly limited, and the manner in which the polyimide resin layer of the desired thickness can be obtained is appropriately adjusted.

(Step (2): Heat treatment step)

Step (2) is a step of applying heat treatment to the coating film to form a polyimide resin layer. By carrying out this step, for example, the polyamic acid contained in the curable resin is subjected to a ring-closing reaction to form a desired resin layer.

The method of heat treatment is not particularly limited, and a known method (such as (The method of heating the supporting substrate of the coating film by statically placing it in a heating oven).

The heating temperature is not particularly limited, but is preferably 300 to 500 ° C. From the viewpoint of lowering the residual solvent rate and further increasing the imidization rate and more excellent effects of the present invention, it is more preferably 350 to 450 ° C. The ring-closing reaction of polyamidic acid is mainly performed at the above-mentioned heating temperature. Therefore, the above-mentioned temperature is hereinafter also referred to as amidine imidization temperature. In addition, as described later, in terms of the effect of the present invention being more excellent, it is preferable that the heating temperature is gradually raised to the fluorene imidization temperature.

There is no particular limitation on the heating time. The optimum time is appropriately selected according to the structure of the curable resin used. In terms of reducing the residual solvent rate and further increasing the imidization rate, and the effect of the present invention is more excellent, The heating time from warming to the imidization temperature is preferably 30 to 180 minutes, and more preferably 60 to 120 minutes. In the case of performing the dry heat treatment described later, the temperature increase time from the temperature at the time of the dry heat treatment to the amidation temperature may be within the above range. In addition, the heating rate during heating is not particularly limited, and it is preferred to increase the temperature at a substantially constant rate (constant heating rate), and it is preferable to use the heating start temperature (in the case of over-drying heat treatment, the drying temperature) ) The value obtained by dividing the difference between the specific imidization temperature and the specific heating time. Specifically, in the case where the heating start temperature is 120 ° C, the temperature of the imidization is 350 ° C, and the temperature rise time is 120 minutes, the temperature increase rate is preferably about (350-120) / 120 ° C to 1.9 ° C / min.

The retention time at the fluorene imidization temperature is preferably 30 to 120 minutes.

The heating environment is not particularly limited, for example, it is performed in the atmosphere, under vacuum, or under an inert gas.

Furthermore, the heat treatment can be performed in stages at different temperatures.

Furthermore, before the treatment at the above heating temperature, a drying and heating treatment for removing volatile components (solvents) in the coating film may be performed as necessary. The temperature conditions of the dry heat treatment are not particularly limited, and in terms of the effect of the present invention being more excellent, the heat treatment at 40 to 200 ° C is preferred. The drying time is not particularly limited, and the effect of the present invention is more excellent. From the aspect, it is preferably 15 to 120 minutes, and more preferably 30 to 60 minutes. Furthermore, the drying and heating treatment can be performed in stages at different temperatures.

Therefore, as one of the preferred forms of this step (2), a form in which the above-mentioned heat treatment at 350 to 450 ° C. is performed after drying and heating treatment at the above-mentioned temperature can be cited.

A polyimide resin layer containing a polyimide resin is formed by going through the above step (2).

There is no particular limitation on the fluorinated imidization rate of the polyfluorene imine resin. In terms of the effect of the present invention being more excellent, it is preferably 99.0% or more, more preferably 99.5% or more.

Regarding the method for measuring the imidization ratio, the case where the curable resin is heated at 350 ° C. for 2 hours under a nitrogen atmosphere is set to be 100%, and it is derived from the IR spectrum of the curable resin. The peak value of the sulfonium imine carbonyl group: an intensity ratio of a peak intensity of about 1780 cm ^{-1 to} a peak intensity that does not change before and after heat treatment (for example, a peak derived from a benzene ring: about 1500 cm ^-1 ).

Furthermore, in the step (1), a curable resin that becomes a polyimide resin having a repeating unit represented by the formula (I) by thermal curing is applied to a glass substrate to produce a coating film, but The composition is not limited to this form, and for example, a composition including a polyimide resin represented by the formula (I) and a solvent may be applied to form a coating film.

<Complex and electronic device>

The composite includes a glass substrate 4 and a resin layer 6.

The light transmittance of the composite is not particularly limited. When it is used in an OLED application where light does not need to be transmitted to the top of the back substrate, it may be 90% or less, or 80% or less.

Next, the electronic device will be described.

Examples of the electronic device include an image display panel, a solar cell, a thin film secondary battery, an imaging device (Charge Coupled Device (CCD), and a complementary metal oxide semiconductor (CMOS). Etc.), pressure sensor, acceleration sensor, biosensor, etc. Examples of the image display panel include a liquid crystal panel (LCD), a plasma display panel (PDP), an organic EL panel (OLED), and electronic paper. The electronic device includes a composite body having the above-mentioned structure and an element formed on the composite body.

FIG. 3 is a view showing an organic EL panel (OLED) according to an embodiment of the present invention. The organic EL panel 70 includes, for example, a composite body 2, a pixel electrode 72, an organic layer 74, a counter electrode 76, a sealing plate 78, and the like. The organic layer 74 includes at least a light emitting layer, and optionally includes a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. For example, the organic layer 74 includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer in this order from the anode side. The pixel electrode 72, the organic layer 74, the counter electrode 76, and the like constitute a top emission organic EL element 71. The organic EL element may be a bottom emission type.

FIG. 4 is a diagram showing a liquid crystal panel according to an embodiment of the present invention. The liquid crystal panel 80 is composed of a TFT substrate 82, a CF substrate 84, a liquid crystal layer 86, and the like. The TFT substrate 82 is formed by patterning TFT elements (thin film transistor elements) 83 and the like on the composite 2 (for example, the glass substrate 4 constituting the composite 2). The CF substrate 84 is formed by patterning a color filter element 85 on another composite body 2 (for example, the glass substrate 4 constituting the composite body 2). The liquid crystal layer 86 is formed between the TFT substrate 82 and the CF substrate 84. The TFT substrate 82 and the CF substrate 84 correspond to electronic devices described in the scope of the patent application.

Fig. 5 is a diagram showing a solar cell according to an embodiment of the present invention. The solar cell 90 includes, for example, a composite body 2, a transparent electrode 92, a silicon layer 94, a reflective electrode 96, a sealing plate 98, and the like. The silicon layer is composed of, for example, a p-layer (a layer doped to a p-type), an i-layer (a light-absorbing layer), an n-layer (a layer doped to an n-type), and the like from the anode side. A silicon-type solar cell element 91 is constituted by a transparent electrode 92, a silicon layer 94, a reflective electrode 96, and the like. The solar cell element may be a compound type, a dye-sensitized type, a quantum dot type, or the like.

Fig. 6 is a view showing a thin film secondary battery according to an embodiment of the present invention. The thin film secondary battery 100 includes, for example, a composite body 2, a transparent electrode 102, an electrolyte layer 104, a current collecting layer 106, The sealing layer 108 and the sealing plate 109 are configured. The thin film secondary battery element 101 is composed of a transparent electrode 102, an electrolyte layer 104, a current collecting layer 106, a sealing layer 108, and the like. In addition, the thin film secondary battery element 101 of this embodiment is a lithium ion type, and may be a nickel-hydrogen type, a polymer type, a ceramic electrolyte type, or the like.

Fig. 7 is a diagram showing an electronic paper according to an embodiment of the present invention. The electronic paper 110 includes, for example, a composite body 2, a TFT layer 112, a layer 114 containing an electrical medium (for example, a microcapsule), a transparent electrode 116, and a front panel 118. The electronic paper element 111 is composed of a TFT layer 112, a layer 114 including an electrical medium, and a transparent electrode 116. The electronic paper element can be any of microcapsule type, transverse electric field type, twisted ball type, particle moving type, electronic jet type, and polymer network type.

[Example]

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited to these examples. Example 1 is an example, and Examples 2 and 3 are comparative examples.

In the following examples, as the glass substrate, a glass substrate X (average thickness of 100 μm, thickness deviation in the width direction of 1 μm or less, alkali-free glass, thermal expansion coefficient of 4 × 10 ⁻⁶ / ° C., and tensile elastic modulus of 77 GPa) was used. There are many small cracks on the surface of the glass substrate X. The micro-cracks have a width W of about 10 to 100 nm and a depth d of 10 μm or less.

The glass substrate X is produced by a float method. Specifically, molten glass is formed by flowing on molten tin to form a strip shape. After the formed glass is slowly cooled, the cooled glass is cut to a desired size. In the slow cooling step and the cutting step, the glass is supported by the air pressure of the compressed air so that the glass is not in contact with solid objects. In the cutting step, a laser cutting method, which is a non-contact cutting method, is used.

<Production Example 1: Production of Polyamic Acid Solution (P1)>

P-phenylenediamine (10.8 g, 0.1 mol) was dissolved in 1-methyl-2-pyrrolidone (226.0 g) and stirred at room temperature. BPDA (3,3 ', 4,4'-bisphenyltetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride) was added thereto over 1 minute (29.4 g, 0.1 mol), and stirred at room temperature for 2 hours to obtain a polyamic acid having a repeating unit represented by the formula (2-1) and / or formula (2-2) and having a solid component concentration of 20 mass % Polyamine solution (P1). When the viscosity of this solution was measured, it was 3000 centipoise at 20 ° C.

The viscosity was obtained by measuring a rotational viscosity at 20 ° C. using a DVL-BII digital viscometer (B-type viscometer) manufactured by Tokimec (stock).

Moreover, X in the repeating unit represented by Formula (2-1) and / or Formula (2-2) contained in polyamic acid is a base represented by Formula (X1), and A is Formula (A1) The indicated base.

<Example 1>

First, the glass substrate X is cleaned by pure water cleaning and then UV cleaning.

Next, a polyamic acid solution (P1) was applied on the first main surface of the glass substrate X by a spin coater (revolution number: 2000 rpm, 15 seconds), so that the glass substrate X was provided with polyamic acid. Coating film (coating film amount: 100g / m ² ).

The polyamino acid is a resin obtained by reacting a compound represented by the formula (Y1) with a compound represented by the formula (B1).

Next, it was heated in the air at 60 ° C for 30 minutes, and then heated at 120 ° C for 30 minutes, and then heated to 350 ° C over 2 hours and held at 350 ° C for 1 hour. The coating was heated to form a resin layer (average thickness) : 25 μm). The formed resin layer contains a polyimide resin having a repeating unit represented by the following formula (X in formula (I) contains a base represented by formula (X1), and A contains a base represented by formula (A1)) . Furthermore, the imidization rate of fluorene was 99.7%.

<Example 2>

The heating conditions of the coating film were set to be heated at 60 ° C for 30 minutes, and then heated at 120 ° C for 30 minutes, and then directly heated in an oven at 350 ° C for 1 hour, except that the same method as in Example 1 was used. A glass composite was obtained.

<Example 3>

After the resin layer (polyimide film) was formed by the same method as in Example 1, the polyimide film was temporarily peeled to overlap with another glass substrate X. Using "HAL-TEC" manufactured by Sankyo, The press-in amount was set to 1 mm, and roll lamination was performed in the atmosphere.

<Measurement of various parameters>

(`` D _f / d '')

The depth d of the micro-cracks is obtained by performing a damage test on the glass substrate X described later and then directly observing the damage origin with an optical microscope.

For the measurement of the depth d _f of the resin, first, by spin coating (2000 rpm), the surface of the glass substrate X was coated with 3-aminopropyltriethoxysilane (KBM903) dissolved in 0.1% by mass. Isopropanol solution. Then, after drying at 80 ° C for 10 minutes, a spin coater (revolution number: 2000 rpm, 15 seconds) was used to contain a fluorescent isothiocyanate (concentration: 0.01 (mmol / l)) and a water-soluble resin (poly An aqueous solution of vinyl alcohol) is applied to the first main surface of the glass substrate X. After the coating treatment, the glass substrate X was rinsed three times with pure water, dried, and then subjected to a damage test described later. Thereafter, the origin of the damage was observed using a fluorescence microscope (Olympus), and the depth d _{f was} observed. The concentration of polyvinyl alcohol in the aqueous solution is adjusted so that the viscosity of the aqueous solution and the viscosity of the polyamic acid solution (P1) are the same.

In addition, the method of measuring the depth d _f by using a fluorescence microscope was disclosed above. After performing the damage test described below on the obtained composite, the origin of the damage was directly observed with an optical microscope. As a result, the depth obtained from the fluorescence microscope was observed. The depth d _f is an equivalent value.

In addition, when it is difficult to measure with a microscope, the theoretical value is obtained from the fracture stress and stress intensity factor based on the basic formula of fracture mechanics d = (K / 2σ) ² ("Ceramic Destruction" P68). And use that value.

(Elongation at break of resin layer TE)

The breaking elongation TE of the resin layer (polyimide resin layer) is measured in accordance with ASTM D882-12.

(Residual stress σ _{S of} resin layer and tensile elastic modulus E _resin )

The yield stress σ _S and the tensile elastic modulus E _resin of the resin layer (polyimide resin layer) are measured in accordance with JIS-C-2151: 2006.

Furthermore, regarding the elongation at break TE of the resin layer (polyimide resin layer), the yield stress σ _S of the resin layer, and the tensile elastic modulus E _resin of the resin layer, the resin layer was peeled from the obtained composite. The above measurement was performed. When the resin layer cannot be peeled off, the glass substrate is dissolved with hydrofluoric acid to obtain a resin layer for measurement.

<Evaluation (damage test)>

The average breaking strength of the glass substrate when the resin layer prepared in Examples 1 to 3 was prepared by the bending test apparatus of FIG. 8 was measured.

Hereinafter, first, a method for measuring the average breaking strength of a glass substrate when a resin layer is not present will be described with reference to FIG. 8.

FIG. 8 is a diagram showing a bending test apparatus for detecting the average breaking strength of the glass substrate of the present invention. In FIG. 8, if the lower support plate moves to the left in the figure with respect to the upper support plate in the state shown by the solid line, it becomes the state shown by the single-dot chain line.

As shown in FIG. 8, the bending test apparatus 10 includes an upper support tray 14 as a first support tray and a lower support tray 16 as a second support tray. The test sheet 18 is placed on the upper support tray 14 and the lower support tray 16. Bend between.

The test sheet 18 was made at the same time as the glass substrate for which the average breaking strength was to be known. The produced glass substrate is processed and produced. Glass substrates made at the same time (for example, glass substrates of the same batch) can be regarded as having the same degree of damage on the surface. In addition, the test sheet 18 may be cut out by itself from a glass substrate that wants to know the average breaking strength.

The test sheet 18 is formed in a rectangular shape in a natural state without external force. The short side length of the test sheet 18 is 100 mm, and the long side length of the test sheet 18 is 150 mm.

The upper support plate 14 supports the test sheet 18. The support surface 14a of the upper support plate 14 is a flat surface facing downward. A short side portion of the test sheet 18 is fixed to the supporting surface 14 a of the upper supporting plate 14 by, for example, an adhesive tape or the like.

The lower support tray 16 supports the test sheet 18 in the same manner as the upper support tray 14. The support surface 16a of the lower support plate 16 is a flat surface facing upward. The other short side portion of the rectangular test sheet 18 is placed on the support surface 16 a of the lower support plate 16 and fixed by static friction. In order to prevent the positional deviation of the test sheet 18, a stopper 17 is provided on the support surface 16 a of the lower support plate 16 to be in contact with the other short side portion of the test sheet 18.

In this bending test apparatus 10, first, an operator adjusts the distance D between the support surface 14a of the upper support plate 14 and the support surface 16a of the lower support plate 16 in parallel with each other so that the upper support plate 14 and the lower The test sheet 18 bent between the side support discs 16 generates a specific tensile stress.

The tensile stress σ generated at the tip of the curved portion of the test sheet 18 (the right end of the test sheet 18 in FIG. 8) can be calculated based on the following formula (2).

σ = A × E × t / (D-t) ‧‧‧ (2)

In the above formula (2), A is a constant (1.198) inherent in the test, E is a tensile elastic modulus of the test sheet 18, and t is a thickness of the test sheet 18. As is clear from the formula (2), the narrower the interval D (D> 2 × t), the larger the tensile stress σ.

Then, the operator moves the position of the lower support disc 16 relative to the upper support disc 14 in a specific direction once while maintaining the interval D. The moving speed is 10 mm / s, the moving distance is 100 mm, and the moving direction is a direction perpendicular to the short side of the test sheet 18.

In this way, an operator checks whether a crack is formed in the test sheet 18 bent between the upper support pan 14 and the lower support disc 16. Whether or not a crack is formed is confirmed using an AE sensor that detects the presence of AE (Acoustic Emission) waves generated when a crack is formed.

When no crack is formed in the test sheet 18, the operator narrows the interval D between the support surface 14a of the upper support plate 14 and the support surface 16a of the lower support plate 16 in parallel with each other. Thereby, the test sheet 18 bent between the upper support plate 14 and the lower support plate 16 generates a tensile stress higher than the previous time.

Next, the operator moves the position relative to the lower support tray 16 relative to the upper support tray 14 while maintaining the interval D, and inspects the test sheet 18 bent between the upper support tray 14 and the lower support tray 16. Whether cracks are formed. The interval D is narrowed in stages and the tensile stress σ applied to the test sheet 18 is increased in stages until cracks are formed in the test sheet 18, thereby knowing the breaking strength of the test sheet 18. The tensile stress σ when the test sheet 18 is broken is used as the breaking strength.

The average value of the breaking strength of the five test sheets 18 is used as the average breaking strength of the five test sheets 18.

Next, a method for measuring the average breaking strength of a composite having a resin layer will be described. When the resin layer is present, the bending test apparatus shown in FIG. 8 is used in the same manner as in the case where the resin layer is not present, and a bending test is performed to generate tensile stress on the main surface of the glass substrate bonded to the resin layer. The tensile stress σ generated at the tip of the bent portion of the main surface of the glass substrate can be calculated by the following formula (3).

σ = A × E × t / (D'-t) ‧‧‧ (3)

In the above formula (3), A is a constant (1.198) inherent in the test, E is the tensile elastic modulus of the glass substrate, t is the thickness of the glass substrate, and D ′ is given by “D '= D-2 × u ". u represents the thickness of the resin layer. Due to the presence of the resin layer, the distance between the upper end and the lower end of the glass substrate is shorter than the interval D by 2 × u. Furthermore, the amount of displacement of the neutral surface of the glass substrate due to the presence of the resin layer is 5% or less of the thickness t of the glass substrate, which hardly affects the calculation result of the tensile stress σ, so it can be ignored. The so-called neutral plane is a plane where neither tensile stress nor compressive stress is generated, and when there is no resin layer, it is the center plane in the thickness direction of the glass substrate. The amount of displacement of the neutral plane can be calculated using a formula commonly used in material mechanics. The tensile stress σ _b when the glass substrate is broken is used as the breaking strength.

Using the above device, the improvement rate of the average breaking strength of the glass substrate realized by the presence of the reinforcing layer (resin layer) was calculated. The improvement rate is a value when the average breaking strength of the glass substrate in the case where there is no reinforcing layer is used as a reference (100%). As the reference average breaking strength in Examples 1 to 3, the average breaking strength (154 MPa) of the glass substrate X was used.

In addition, the flexibility of the composites prepared in Examples 1 to 3 was evaluated by the increase rate of the flexural rigidity of the composites. Here, the "rise rate of flexural rigidity" means the rise rate of the flexural rigidity of the composite when the flexural rigidity of the glass substrate when the resin layer is not present is used as a reference. The deflection stiffness can be calculated using a formula commonly used in structural mechanics. The lower the rate of increase in flexural stiffness, the better the flexibility.

The evaluation results are shown in Table 1.

As shown in Example 1 of Table 1, it was confirmed that the composite of the present invention exhibited a desired effect. In addition, since the flexural rigidity did not increase too much, the flexibility did not decrease.

On the other hand, Examples 2 and 3 which did not satisfy the requirements of the present invention did not achieve the desired effect. fruit.

As mentioned above, although embodiment of a composite body etc. were described, this invention is not limited to the said embodiment. The present invention can be changed or improved within the scope of the subject matter described in the scope of patent application.

The present invention has been described in detail and with reference to specific embodiments, but it is clear to those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application filed on June 16, 2014 (Japanese Patent Application No. 2014-123308), the contents of which are incorporated herein by reference.

Claims (6)

A composite body comprising a glass substrate having microcracks on the surface and a resin layer disposed on the glass substrate, and the resin of the resin layer penetrates into at least a part of the interior of the microcracks, and the resin is distanced from the surface of the glass substrate The product of the ratio of the depth of deep d _f to the depth d of the micro-cracks (d _f / d), the elongation at break TE (%) of the resin layer, and the relief stress σ _S (MPa) of the resin layer ( The ratio (d _f / d) × elongation at break TE × drop stress σ _S ) is 400 MPa ·% or more, and the tensile elastic modulus E _resin of the resin layer is 1.0 GPa or more. For example, the composite of claim 1, wherein the average thickness of the glass substrate is 10 to 200 μm. For example, the composite of claim 1, wherein the average thickness of the resin layer is 10 to 100 μm. For example, the composite of claim 2, wherein the average thickness of the resin layer is 10 to 100 μm. The composite according to any one of claims 1 to 4, wherein the resin layer contains polyimide. An electronic device includes the composite according to any one of claims 1 to 5 and an element formed on a glass substrate of the composite.